PRIORART
Lithium batteries are used to power portable electronics and electric vehicles
owing to their high energy and power density. Conventional lithium batteries make
use of a liquid electrolyte that is composed of a lithium salt dissolved in an organic
solvent. The aforementioned system raises security questions as the organic
20 solvents are flammable. Lithium dendrites forming and passing through the liquid
electrolyte medium can cause short circuit and produce heat, which result in
accident that leads to serious injuries. Since the electrolyte solution is a flammable
liquid, there is a concern of occurrence of leakage, ignition or the like when used in
a battery. Taking such concern into consideration, development of a solid
25 electrolyte having a higher degree of safety is expected as an electrolyte for a
next-generation lithium battery.
Non-flammable inorganic solid electrolytes offer a solution to the security problem.
Furthermore, their mechanic stability helps suppressing lithium dendrite formation,
preventing self-discharge and heating problems, and prolonging the life-time of a
30 battery.
Solid sulfide electrolytes are advantageous for lithium battery applications due to
their high ionic conductivities and mechanical properties. These electrolytes can
be pelletized and attached to electrode materials by cold pressing, which
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eliminates the necessity of a high temperature assembly step. Elimination of the
high temperature sintering step removes one of the challenges against using
lithium metal anodes in lithium batteries. Due to the wide-spread use of all solid
state lithium batteries, there is an increasing demand for solid state electrolytes
5 having a high conductivity for lithium ions.
As an example of a relatively stable solid electrolyte, Li4P2Se, lithium
hexathiohypodiphosphate, has been identified in several high temperature
preparations of lithium thiophosphate electrolytes as a synthesis or decomposition
product. Its characteristic P-P bond may be partly responsible for its relative high
10 thermal, moisture and electrochemical stabilities. However, ionic conductivity of
Li4P2Se is modest, impairing its use as solid electrolyte.
There is however a need for new solid sulfide electrolytes having optimized
performances from the viewpoint of achieving higher output of a battery, such as
higher ionic conductivity and lower activation energy, without compromising other
15 important properties like chemical and mechanical stability.
INVENTION
Surprisingly it has been found that new solid sulfide electrolytes having higher
ionic conductivity and lower activation energy in comparison with usual Li4P2Se
20 materials may be obtained by using zinc dopant. The new LiZnPS solid materials
of the invention also exhibits at least similar chemical and mechanical stability and
processability like those conventional lithium sulfide electrolytes. Solid materials of
the invention may also be prepared with improved productivity and allowing a
control of the morphology of the obtained product. Furthermore, solid materials of
25 the invention exhibit a lower amount of raw materials impurity, such as Li2S. Solid
materials of the invention exhibit also a lower amount of undesired phases, such
as Gamma-Li3PS4. Also, phases of the invention offer an improvement in the ionic
conductivity at room temperature of three order of magnitude compared to Li4P2Se
and better than the previous dopant reported with Sc and Mg. Additionally these
30 phases exhibit an enhanced moisture stability with a lower release of H2S
compared to undoped Li4P2Se.
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The present invention refers then to a solid material comprising Li, Zn, P and S
elements and exhibiting at least peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°,
27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when analyzed by x-ray diffraction using
CuKa radiation at 25°C. Preferably said solid materials have peaks at position of:
5 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when
analyzed by x-ray diffraction using CuKa radiation at 25°C.
10
Preferably solid material of the invention is a solid material according to general
formula (I) as follows:
Li4-2xZnxP2Ss (I)
wherein 0 < x :::; 1, preferably x is chosen from 0.2 to 0. 7 and more preferably from
0.33 to 0.5.
The invention also concerns a method for producing a solid material of the
15 invention, such as a solid material comprising Li, Zn, P and S elements and
exhibiting at least peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°,
32.1 °+/- 0.5°, 32.6°+/- 0.5° when analyzed by x-ray diffraction using CuKa
radiation at 25°C, preferably a solid material according to general formula (I) as
follows:
20
wherein 0 < x :::; 1 ;
comprising at least bringing at least lithium sulfide, phosphorous sulfide and zinc
compound, optionally in one or more solvents, then proceeding with a heat
treatment at a temperature in the range of from 375°C to 900°C, under an inert
25 atmosphere, thereby forming the solid material.
The invention also refers to a solid material susceptible to be obtained by said
process.
30 The invention also refers to a process for the preparation of a solid material
according to general formula (I) as follows:
Li4-2xZnxP2Ss (I)
wherein 0 < x :::; 1 ;
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comprising at least the process steps of:
a) obtaining a composition by admixing stoichiometric amounts of lithium sulfide,
phosphorous sulfide, and a zinc compound in order to obtain Li4-2xZnxP2S7,
optionally in one or more solvents, under an inert atmosphere;
5 b) applying a mechanical treatment to the composition obtained in step a);
c) optionally removing at least a portion of the one or more solvents from the
composition obtained on step b), so that to obtain a solid residue;
d) heating the obtained residue obtained in step c) at a temperature in the range of
from 375°C to 900°C, under an inert atmosphere, thereby forming the solid
10 material; and
e) optionally treating the solid material obtained in step d) to the desired particle
size distribution.
The invention furthermore concerns a solid material susceptible to be obtained by
15 said process.
The invention also refers to the use of a solid material comprising Li, Zn, P and S
elements and exhibiting at least peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°,
27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when analyzed by x-ray diffraction using
20 CuKa radiation at 25°C, preferably a solid material of formula (I) as follows:
wherein 0 < x :::; 1 ;
as solid electrolyte.
Li4-2xZnxP2Ss (I)
25 The invention also refers to a solid electrolyte comprising at least a solid material
comprising Li, Zn, P and S elements and exhibiting at least peaks at position of:
13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when
analyzed by x-ray diffraction using CuKa radiation at 25°C, preferably a solid
material of formula (I) as follows:
30
wherein 0 < x :::; 1 .
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The invention also concerns an electrochemical device comprising at least a solid
electrolyte comprising at least a solid material comprising Li, Zn, P and S elements
and exhibiting at least peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/-
0.50, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when analyzed by x-ray diffraction using CuKa
5 radiation at 25°C, preferably a solid material of formula (I) as follows:
Li4-2xZnxP2Ss (I)
wherein 0 < x :::; 1 .
The invention also refers to a solid state battery comprising at least a solid
10 electrolyte comprising at least a solid material comprising Li, Zn, P and S elements
and exhibiting at least peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/-
0.50, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when analyzed by x-ray diffraction using CuKa
radiation at 25°C, preferably a solid material of formula (I) as follows:
Li4-2xZnxP2Ss (I)
15 wherein 0 < x :::; 1 .
The present invention also concerns a vehicle comprising at least a solid state
battery comprising at least a solid electrolyte comprising at least a solid material
comprising Li, Zn, P and S elements and exhibiting at least peaks at position of:
20 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when
analyzed by x-ray diffraction using CuKa radiation at 25°C, preferably a solid
material of formula (I) as follows:
wherein 0 < x :::; 1 .
25
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DEFINITIONS
Throughout this specification, unless the context requires otherwise, the word
"comprise" or "include", or variations such as "comprises", "comprising", "includes",
including" will be understood to imply the inclusion of a stated element or method
5 step or group of elements or method steps, but not the exclusion of any other
element or method step or group of elements or method steps. According to
preferred embodiments, the word "comprise" and "include", and their variations
mean "consist exclusively of".
As used in this specification, the singular forms "a", "an" and "the" include plural
1 0 aspects unless the context clearly dictates otherwise. The term "and/or" includes
the meanings "and", "or'' and also all the other possible combinations of the
elements connected to this term.
The term "between" should be understood as being inclusive of the limits.
Ratios, concentrations, amounts, and other numerical data may be presented
15 herein in a range format. It is to be understood that such range format is used
merely for convenience and brevity and should be interpreted flexibly to include
not only the numerical values explicitly recited as the limits of the range, but also
to include all the individual numerical values or sub-ranges encompassed within
that range as if each numerical value and sub-range is explicitly recited. For
20 example, a temperature range of about 120°C to about 150°C should be
interpreted to include not only the explicitly recited limits of about 120°C to about
150°C, but also to include sub-ranges, such as 125°C to 145°C, 130°C to 150°C,
and so forth, as well as individual amounts, including fractional amounts, within the
specified ranges, such as 122.2°C, 140.6°C, and 141.3°C, for example.
25 The term "electrolyte" refers in particular to a material that allows ions, e.g., Li+, to
migrate therethrough but which does not allow electrons to conduct therethrough.
Electrolytes are useful for electrically isolating the cathode and anodes of a battery
while allowing ions, e.g., Li+, to transmit through the electrolyte. The "solid
electrolyte" according to the present invention means in particular any kind of
30 material in which ions, for example, Li+, can move around while the material is in a
solid state.
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As used herein, the term "crystalline phase" refers to a material of a fraction of a
material that exhibits a crystalline property, for example, well-defined x-ray
diffraction peaks as measured by X-Ray Diffraction (XRD).
As used herein, the term "peaks" refers to (28) positions on the x-axis of an XRD
5 powder pattern of intensity v. degrees (28) which have a peak intensity
substantially greater than the background. In a series of XRD powder pattern
peaks, the primary peak is the peak of highest intensity which is associated with
the compound, or phase, being analyzed. The second primary peak is the peak of
second highest intensity. The third primary peak is the peak of third highest
1 0 intensity.
The term "electrochemical device" refers in particular to a device which generates
and/or stores electrical energy by, for example, electrochemical and/or
electrostatic processes. Electrochemical devices may include electrochemical cells
such as batteries, notably solid state batteries. A battery may be a primary (i.e.,
15 single or "disposable" use) battery, or a secondary (i.e., rechargeable) battery.
As used herein, the terms "cathode" and "anode" refer to the electrodes of a
battery. During a charge cycle in a Li-secondary battery, Li ions leave the cathode
and move through an electrolyte and to the anode. During a charge cycle,
electrons leave the cathode and move through an external circuit to the anode.
20 During a discharge cycle in a Li-secondary battery, Li ions migrate towards the
cathode through an electrolyte and from the anode. During a discharge cycle,
electrons leave the anode and move through an external circuit to the cathode.
It is understood that the term "vehicle" or "vehicular" or other similar term as used
herein is inclusive of motor vehicles in general such as passenger automobiles
25 including sports utility vehicles (SUV), buses, trucks, various commercial vehicles,
watercraft including a variety of boats and ships, aircraft, and the like, and includes
hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogenpowered
vehicles and other alternative fuel vehicles (e.g. fuels derived from
resources other than petroleum). As referred to herein, a hybrid vehicle is a
30 vehicle that has two or more different sources of power, for example both
gasoline-powered and electric-powered vehicles.
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DETAILED INVENTION
The present invention refers then to a solid material comprising Li, Zn, P and S
elements and exhibiting at least peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°,
27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when analyzed by x-ray diffraction using
5 CuKa radiation at 25°C. Preferably said solid materials as peaks at position of:
13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when
analyzed by x-ray diffraction using CuKa radiation at 25°C.
10
The invention then also relates to a solid material according to general formula (I)
Li4-2xZnxP2Ss (I)
wherein 0 < x :::; 1 .
The solid material of the invention is neutrally charged. It is understood that
formula (I) is an empirical formula (gross formula) determined by means of
elemental analysis. Accordingly, formula (I) defines a composition which is
15 averaged over all phases present in the solid material.
0 < x :::; 1, preferably xis chosen from 0.2 to 0.7 and more preferably from 0.33 to
0.5, notably x is 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65
and 0.66 or any range made from these values.
The solid material of the invention may be amorphous (glass) and/or crystallized
20 (glass ceramics). Only part of the solid material may be crystallized. Preferably the
solid material of the invention is fully crystalline. The crystallized part of the solid
material may comprise only one crystal structure or may comprise a plurality of
crystal structures.
Indexation in the trigonal space group P-31 m is possible. The cristallographic
25 space group of the solid material of the present invention is preferably space
group 162 (P-31 m). In this space group, cell parameters of the solid materials of
the present invention may range from a=b=6.01 Angstrom to 6.11 Angstrom and
c=6.55 Angstrom to c=6.64 Angstrom, as measured by x-ray diffraction using
CuKa radiation at 25°C, and further calculated with a dedicated software, such as
30 Fullprof software, using a refinement method such as Rietveld and Le Bail
refinement. The volume per formula atom may range from 206 A3/f.u to 215 A3/f.u.
For instance for solid material Li3.33Zno.33P2Se, cell parameters are a= b= 6.06A
and c=6.59A and volume per formula atom is 209 A3/f.u.
5
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Preferably solid materials of formula (I) according to the present invention are
chosen in the group consisting of: Lb.sZno.1P2Se, Li3.eZno.2P2Se, Li3.sZno.2sP2Se,
Li3.33Zno.33P2Se, li3.2Zno.4P2Se, li3Zno.sP2Se, and Li2.eeeZno.eeeP2Se.
The composition of the compound of formula (I) may notably be determined by
chemical analysis using techniques well known to the skilled person, such as for
instance a X-Ray Diffraction (XRD) and an Inductively Coupled Plasma-Mass
Spectrometry (ICP-MS).
10 Solid materials of the invention may be in powder form with a distribution of
particle diameters having a 050 preferably comprised between 0.05 1-1m and 10
1-Jm. The particle size can be evaluated with SEM image analysis or laser
diffraction analysis.
050 has the usual meaning used in the field of particle size distributions. Dn
15 corresponds to the diameter of the particles for which n% of the particles have a
diameter which is less than Dn. 050 (median) is defined as the size value
corresponding to the cumulative distribution at 50%. These parameters are usually
determined from a distribution in volume of the diameters of a dispersion of the
particles of the solid material in a solution, obtained with a laser diffractometer,
20 using the standard procedure predetermined by the instrument software. The laser
diffractometer uses the technique of laser diffraction to measure the size of the
particles by measuring the intensity of light diffracted as a laser beam passes
through a dispersed particulate sample. The laser diffractometer may be the
Mastersizer 3000 manufactured by Malvern for instance.
25 050 may be notably measured after treatment under ultrasound. The treatment
under ultrasound may consist in inserting an ultrasonic probe into a dispersion of
the solid material in a solution, and in submitting the dispersion to sonication.
The invention also concerns a method for producing a solid material comprising Li,
30 Zn, P and S elements and exhibiting at least peaks at position of: 13.4° +/- 0.5°,
16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when analyzed by x-ray
diffraction using CuKa radiation at 25°C, preferably a solid material according to
general formula (I) as follows:
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wherein 0 < x :::; 1 ;
10
Li4-2xZnxP2Ss (I)
PCT/EP2021/063911
comprising at least bringing at least lithium sulfide, phosphorous sulfide and zinc
compound, optionally in one or more solvents, then proceeding with a heat
5 treatment at a temperature in the range of from 375°C to 900°C, under an inert
atmosphere, thereby forming the solid material.
10
15
One or more lithium sulfide, phosphorous sulfide, and zinc compound may be
used.
Solid materials of the invention may be produced by any methods used in the prior
art known for producing a Li4P2Se, such as for instance a melt extraction method, a
full solution method, a mechanical milling method or a slurry method in which raw
materials are reacted, optionally in one or more solvents.
The invention then refers to a process for the preparation of a solid material
comprising Li, Zn, P and S elements and exhibiting at least peaks at position of:
13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when
analyzed by x-ray diffraction using CuKa radiation at 25°C, said process
20 comprising at least the process steps of:
a) obtaining a composition by admixing stoichiometric amounts of lithium sulfide,
phosphorous sulfide, and a zinc compound, optionally in one or more solvents,
under an inert atmosphere;
b) applying a mechanical treatment to the composition obtained in step a);
25 c) optionally removing at least a portion of the one or more solvents from the
composition obtained on step b), so that to obtain a solid residue;
d) heating the obtained residue obtained in step c) at a temperature in the range of
from 375°C to 900°C, under an inert atmosphere, thereby forming the solid
material; and
30 e) optionally treating the solid material obtained in step d) to the desired particle
size distribution.
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The invention also refers to a process for the preparation of a solid material
according to general formula (1), said process comprising at least the process
steps of:
a) obtaining a composition by admixing stoichiometric amounts of lithium sulfide,
5 phosphorous sulfide, and a zinc compound in order to obtain Li4-2xZnxP2S7,
optionally in one or more solvents, under an inert atmosphere;
b) applying a mechanical treatment to the composition obtained in step a);
c) optionally removing at least a portion of the one or more solvents from the
composition obtained on step b), so that to obtain a solid residue;
10 d) heating the obtained residue obtained in step c) at a temperature in the range of
from 375°C to 900°C, under an inert atmosphere, thereby forming the solid
material; and
15
e) optionally treating the solid material obtained in step d) to the desired particle
size distribution.
Inert atmosphere as used in step a) refers to the use of an inert gas; ie. a gas that
does not undergo detrimental chemical reactions under conditions of the reaction.
Inert gases are used generally to avoid unwanted chemical reactions from taking
place, such as oxidation and hydrolysis reactions with the oxygen and moisture in
20 air. Hence inert gas means gas that does not chemically react with the other
reagents present in a particular chemical reaction. Within the context of this
disclosure the term "inert gas" means a gas that does not react with the solid
material precursors. Examples of an "inert gas" include, but are not limited to,
nitrogen, helium, argon, carbon dioxide, neon, xenon, H2S, 02 with less than 1000
25 ppm of liquid and airborne forms of water, including condensation. The gas can
also be pressurized.
It is preferred that stirring be conducted when the raw materials are brought into
contact with each other under an atmosphere of an inert gas such as nitrogen or
argon. The dew point of an inert gas is preferably -20°C or less, particularly
30 preferably -40°C or less. The pressure may be from 0.0001 Pa to 100 MPa,
preferably from 0.001 Pa to 20 MPa, preferably from 0.01 Pa to 0.5 MPa.
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Preferably in step a), inert atmosphere comprises an inert gas such as H2S, dry
N2, dry Argon or dry air (dry may refer to a gas with less than 800ppm of liquid and
airborne forms of water, including condensation).
The composition ratio of each element can be controlled by adjusting the amount
5 of the raw material compound when the solid material is produced. The precursors
and their molar ratio are selected according to the target stoichiometry for the
production of the solid material of formula (I). The target stoichiometry defines the
ratio between the elements Li, Zn, P and S, which is obtainable from the applied
amounts of the precursors under the condition of complete conversion without side
1 0 reactions and other losses.
Lithium sulfide refers to a compound including one or more of sulfur atoms and
one or more of lithium atoms, or alternatively, one or more of sulfur containing
ionic groups and one or more of lithium containing ionic groups. In certain
preferred aspects, lithium sulfide may consist of sulfur atoms and lithium atoms.
15 Preferably, lithium sulfide is Li2S.
Phosphorus sulfide refers to a compound including one or more of sulfur atoms
and one or more of phosphorus atoms, or alternatively, one or more of sulfur
containing ionic groups and one or more of phosphorus containing ionic groups. In
certain preferred aspects, phosphorus sulfide may consist of sulfur atoms and
20 phosphorus atoms. Non-limiting exemplary phosphorus sulfide may include, but
not limited to, P2Ss, P4S3, P4S1o, P4S4, P4Ss, P4Se, P4S7, P4Ss, and P4Sg.
Zinc compound refers to a compound including one or more of Zn atoms via
chemical bond (e.g., ionic bond or covalent bond) to the other atoms constituting
the compound. In another aspect, zinc compound can be metallic zinc. In certain
25 preferred aspect, the zinc compound may include one or more Zn atoms one or
more non-metal atoms, such as S. Zinc compounds are preferably chosen in the
group consisting of: ZnS and Zn. Zinc compound of the invention may also be a
blend of metallic zinc and elementary sulfur.
Preferably, the solid material of the invention is made by using at least the
30 precursors as follows: Li2S, P2Ss, and ZnS.
Preferably, lithium sulfide, phosphorous sulfide and zinc compound have an
average particle diameter comprised between 0.5 1-1m and 400 1-Jm. The particle
size can be evaluated with SEM image analysis or laser diffraction analysis.
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The solvent may suitably be selected from one or more of polar or non-polar
solvents that may substantially dissolve at least one compound selected from:
lithium sulfide, phosphorus sulfide, and zinc compound. Said solvent may also
substantially suspend, dissolve or otherwise admix the above described
5 components, e.g., lithium sulfide, phosphorus sulfide, and zinc compound.
Solvent of the invention then constitutes in step a) a continuous phase with
dispersion of one or more of the above described components.
Depending on the components and the solvent, some of the components are then
rather dissolved, partially dissolved or under a form of a slurry.(ie. component(s)
10 is/are not dissolved and forming then a slurry with the solvent).
In certain preferred aspect, the solvent may suitably a polar solvent. Solvents are
preferably polar solvents preferably selected in the group consisting of alkanols,
notably having 1 to 6 carbon atoms, such as methanol, ethanol, propanol and
butanol; carbonates, such as dimethyl carbonate; acetates, such as ethyl acetate;
15 ethers, such as dimethyl ether, tetrahydrofuran; organic nitriles, such as
acetonitrile; aliphatic hydrocarbons, such as hexane, pentane, 2-ethylhexane,
heptane, decane, and cyclohexane; and aromatic hydrocarbons, such as xylene
and toluene.
It is understood that references herein to "a solvent" includes one or more mixed
20 solvents.
An amount of about 1 wt% to 80 wt% of the powder mixture and an amount of
about 20 wt% to 99 wt% of the solvent, based on the total weight of the powder
mixture and the solvent, may be mixed. Preferably, an amount of about 25 wt% to
75 wt% of the powder mixture and an amount of 25 wt% to 75 wt% of the solvent,
25 based on the total weight of the powder mixture and the solvent, may be mixed.
Particularly, an amount of about 40 wt% to 60 wt% of the powder mixture and an
amount of about 40 wt % to 60 wt % of the solvent, based on the total weight of
the powder mixture and the solvent, may be mixed.
The temperature of step a) in presence of solvent is preferably between the fusion
30 temperature of the selected solvent and ebullition temperature of the selected
solvent at a temperature where no unwanted reactivity is found between solvent
and admixed compounds. Preferably step a) is done between -20°C and 40°C and
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more preferably between 15°C and 40°C. In absence of solvent step a) is done at
a temperature between -20°C and 200°C and preferably between 15°C and 40°C.
Duration of step a) is preferably between 1 minute and 1 hour.
5 Mechanical treatment to the composition in step b) may be performed by wet or
dry milling; notably be performed by adding the powder mixture to a solvent and
then milling at about 100 rpm to 1000 rpm, notably for a duration from 10 minutes
to 80 hours more preferably for about 4 hours to 40 hours.
Said milling is also known as reactive-milling in the conventional synthesis of LiPS
1 0 compounds.
The mechanical milling method also has an advantage that, simultaneously with
the production of a glass mixture, pulverization occurs. In the mechanical milling
method, various methods such as a rotation ball mill, a tumbling ball mill, a
vibration ball mill and a planetary ball mill or the like can be used. Mechanical
15 milling may be made with or without balls such as Zr02.
In such a condition, lithium sulfide, phosphorous sulfide and zinc compound are
allowed to react in a solvent for a predetermined period of time.
The temperature of step b) in presence of solvent is between the fusion
temperature of the selected solvent and ebullition temperature of the selected
20 solvent at a temperature where no unwanted reactivity is found between solvent
and compounds. Preferably step b) is done at a temperature between -20°C and
80°C and more preferably between 15°C and 40°C. In absence of solvent step a)
is done between -20°C and 200°C and preferably between 15°C and 40°C.
Mechanical treatment to the composition in step b) may also be performed by
25 stirring, notably by using well known techniques in the art, such as by using
standard powder or slurry mixers.
Usually a paste or a blend of paste and liquid solvent may be obtained at the end
of step b).
30 In step c), at least a portion of the solvent is removed notably means to remove at
least about 30%, 40%, 50%, 60%, 70%, 80%, 90% 95% or 1 00%, of the total
weight of a solvent used, or any ranges comprised between these values. Solvent
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removal may be carried out by known methods used in the art, such as
decantation, filtration, centrifugation, drying or a combination thereof.
The temperature in step c) is selected to allow removal of solvent. Preferably when
drying is selected as method for solvent removal, temperature is selected below
5 ebullition temperature and as a function of vapor partial pressure of the selected
solvent.
Duration of step c) is between 1 second and 100 hours, preferably between 1 hour
and 20 hours. Such a low duration may be obtained for instance by using a flash
evaporation, such as by spray drying.
10 It is preferred that step c) be conducted under an atmosphere of an inert gas such
as nitrogen or argon. The dew point of an inert gas is preferably -20°C or less,
particularly preferably -40°C or less. The pressure may be from 0.0001 Pa to 100
MPa, preferably from 0.001 Pa to 20 MPa, preferably from 0.01 Pa to 20 MPa.
Notably the pressure may range from 0.0001 Pa to 0.001 Pa, notably by using
15 ultravacuum techniques. Notably the pressure may range from 0.01 Pa to 0.1 MPa
by using primary vacuum techniques.
In step d) the heating, or thermal treatment, may notably allow to convert the
amorphized powder mixture (glass) obtained above into a solid material crystalline
20 or mixture of glass and crystalline (glass ceramics).
Heat treatment is carried out at a temperature in the range of from 375°C to
900°C, preferably from 400°C to 700°C, more preferably from 550°C to 650°C,
notably for a duration of 1 minute to 1 00 hours, preferably from 4 hours to 40
hours. Heat treatment may start directly at high temperature or via a ramp of
25 temperature at a rate comprised between 1 oC/min to 20°C/min. Heat treatment
may finish with an air quenching or via natural cooling from the heating
temperature or via a controlled ramp of temperature at a rate comprised between
1 °C/min to 20°C/min.
Preferably in step d), inert atmosphere comprises an inter gas such as dry N2, or
30 dry Argon (dry may refer to a gas with less than 800ppm of liquid and airborne
forms of water, including condensation). Preferably in step d) the inert atmosphere
is a protective gas atmosphere used in order to minimize, preferably exclude
access of oxygen and moisture.
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The pressure at the time of heating may be at normal pressure or under reduced
pressure. The atmosphere may be inert gas, such as nitrogen and argon. The dew
point of the inert gas is preferably -20°C or less, with -40°C or less being
particularly preferable. The pressure may be from 0.0001 Pa to 100 MPa,
5 preferably from 0.001 Pa to 20 MPa, preferably from 0.01 Pa to 20 MPa. Notably
the pressure may range from 0.0001 Pa to 0.001 Pa, notably by using ultravacuum
techniques. Notably the pressure may range from 0.01 Pa to 0.1 MPa by using
primary vacuum techniques.
1 0 Without being bound by the theory, heat treatment at step d) allows sublimation of
S element and generation of a solid material according to general formula (1),
notably by the reaction as follows:
(2- x) Li4 _ 2xZnyP257 _(x-y) + (x- y)ZnS = Li4 _ 2xZnxP256 + 5
In step e), it is possible to treat the solid material to the desired particle size
15 distribution. If necessary, the solid material obtained by the process according to
the invention as described above is ground (e.g. milled) into a powder. Preferably,
said powder has a 050 value of the particle size distribution of less than 100 1-Jm,
more preferably less than 10 1-Jm, most preferably less than 5 1-Jm, as determined
by means of dynamic light scattering or image analysis.
20 Preferably, said powder has a 090 value of the particle size distribution of less
than 100 1-Jm, more preferably less than 10 1-Jm, most preferably less than 5 1-Jm, as
determined by means of dynamic light scattering or image analysis. Notably, said
powder has a 090 value of the particle size distribution comprised from 1 1-1m to
100 1-Jm.
25
The invention also refers to a solid material of the invention as solid electrolyte, as
well as a solid electrolyte comprising at least a solid material of the invention.
Said solid electrolytes comprises then at least a solid material of the invention,
notably a solid material of formula (I), and optionally another solid electrolyte, such
30 as a lithium argyrodites, lithium thiophosphates, such as glass or glass ceramics
Li3PS4, Li7PS11, and lithium conducting oxides such as lithium stuffed garnets
Li7la3Zrz012 (LLZO).
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Said solid electrolytes may also optionally comprise polymers such as styrene
butadiene rubbers, organic or inorganic stabilizers such as Si02 or dispersants.
The invention also concerns an electrochemical device comprising a solid
5 electrolyte comprising at least a solid material of the invention, notably a solid
material of formula (I).
Preferably in the electrochemical device, particularly a rechargeable
electrochemical device, the solid electrolyte is a component of a solid structure for
an electrochemical device selected from the group consisting of cathode, anode
1 0 and separator.
Herein preferably the solid electrolyte is a component of a solid structure for an
electrochemical device, wherein the solid structure is selected from the group
consisting of cathode, anode and separator. Accordingly, the solid materials
according to the invention can be used alone or in combination with additional
15 components for producing a solid structure for an electrochemical device, such as
a cathode, an anode or a separator.
The electrode where during discharging a net negative charge occurs is called the
anode and the electrode where during discharging a net positive charge occurs is
called the cathode. The separator electronically separates a cathode and an
20 anode from each other in an electrochemical device.
Suitable electrochemically active cathode materials and suitable electrochemically
active anode materials are well known in the art. In an electrochemical device
according to the invention, the anode preferably comprises graphitic carbon,
metallic lithium, silicon compounds such as Si, SiOx, lithium titanates such as
25 Li4Tis012 or a metal alloy comprising lithium as the anode active material such as
Sn.
In an electrochemical device according to the invention, the cathode preferably
comprises a metal chalcogenide of formula LiM02, wherein M is at least one metal
selected from transition metals such as Co, Ni, Fe, Mn, Cr and V and Q is a
30 chalcogen such as 0 or S. Among these, it is preferred to use a lithium-based
composite metal oxide of formula LiM02, wherein M is the same as defined above.
Preferred examples thereof may include LiCo02, LiNi02, LiNixCo1-x02 (0 < x < 1 ),
and spinel-structured LiMn204. Another preferred examples thereof may include
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lithium-nickel-manganese-cobalt-based metal oxide of formula LiNixMnyCoz02
(x+y+z=1, referred to as NMC), for instance LiNi1t3Mn1t3C01t302,
LiNio.eMno.2Coo.202, and lithium-nickel-cobalt-aluminum-based metal oxide of
formula LiNixCoyAiz02 (x+y+z = 1, referred to as NCA), for instance
5 LiNio.sCoo.1sAio.os02. Cathode may comprise a lithiated or partially lithiated
transition metal oxyanion-based material such as LiFeP04.
For example, the electrochemical device has a cylindrical-like or a prismatic
shape. The electrochemical device can include a housing that can be from steel or
aluminum or multilayered films polymer/metal foil.
1 0 A further aspect of the present invention refers to batteries, more preferably to an
alkali metal battery, in particular to a lithium battery comprising at least one
inventive electrochemical device, for example two or more. Electrochemical
devices can be combined with one another in inventive alkali metal batteries, for
example in series connection or in parallel connection.
15
The invention also concerns a solid state battery comprising a solid electrolyte
comprising at least a solid material of the invention, notably a solid material of
formula (1).
Typically, a lithium solid-state battery includes a positive electrode active material
20 layer containing a positive electrode active material, a negative electrode active
material layer containing a negative electrode active material, and a solid
electrolyte layer formed between the positive electrode active material layer and
the negative electrode active material layer. At least one of the positive electrode
active material layer, the negative electrode active material layer, and the solid
25 electrolyte layer includes a solid electrolyte as defined above.
The cathode of an all-solid-state electrochemical device usually comprises beside
an active cathode material as a further component a solid electrolyte. Also the
anode of an all-solid state electrochemical device usually comprises a solid
electrolyte as a further component beside an active anode material.
30 The form of the solid structure for an electrochemical device, in particular for an
all-solid-state lithium battery, depends in particular on the form of the produced
electrochemical device itself. The present invention further provides a solid
structure for an electrochemical device wherein the solid structure is selected from
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the group consisting of cathode, anode and separator, wherein the solid structure
for an electrochemical device comprises a solid material according to the
invention.
A plurality of electrochemical cells may be combined to an all solid-state battery,
5 which has both solid electrodes and solid electrolytes.
The solid material disclosed above may be used in the preparation of an electrode.
The electrode may be a positive electrode or a negative electrode.
The electrode typically comprises at least:
1 0 - a metal substrate;
- directly adhered onto said metal substrate, at least one layer made of a
composition comprising:
(i) a solid material comprising Li, Zn, P and S elements and exhibiting at least
peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°,
15 32.6°+/- 0.5° when analyzed by x-ray diffraction using CuKa radiation at 25°C,
preferably a solid material of formula (I) as follows:
Li4-2xZnxP2Ss (I)
wherein 0 < x :::; 1 ;
(ii) at least one electro-active compound (EAC);
20 (iii) optionally at least one lithium ion-conducting material (LiCM) other than the
solid material of the invention;
(iv) optionally at least one electro-conductive material (ECM);
(v) optionally a lithium salt (LIS);
(vi) optionally at least one polymeric binding material (P).
25 The electro-active compound (EAC) denotes a compound which is able to
incorporate or insert into its structure and to release lithium ions during the
charging phase and the discharging phase of an electrochemical device. An EAC
may be a compound which is able to intercale and deintercalate into its structure
lithium ions. For a positive electrode, the EAC may be a composite metal
30 chalcogenide of formula LiMe02 wherein:
-Me is at least one metal selected in the group consisting of Co, Ni, Fe, Mn, Cr, AI
and V;
- Q is a chalcogen such as 0 or S.
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The EAC may more particularly be of formula LiMe02. Preferred examples of EAC
include LiCo02, LiNi02, LiMn02, LiNixC01-x02 (0 < x < 1 ), LiNixCOyMnz02 (0 < x, y,
z < 1 and x+y+z=1) for instance LiNi1t3Mn1t3C01t302, LiNio.eMno.2Coo.202,
LiNio.sMno.1Coo.102, Li(NixCoyAiz)02 (x+y+z=1) and spinel-structured LiMn204 and
5 Li (Nio.sMn1.5)04.
The EAC may also be a lithiated or partially lithiated transition metal oxyanionbased
electro-active material of formula M1M2(J04)fEH wherein:
- M1 is lithium, which may be partially substituted by another alkali metal
representing less than 20% of M1;
10 - M2 is a transition metal at the oxidation level of +2 selected from Fe, Co, Mn, Ni
or mixtures thereof, which may be partially substituted by one or more additional
metals at oxidation levels between +1 and +5 and representing less than 35% of
the M2 metals, including 0;
- J04 is any oxyanion wherein J is either P, S, V, Si, Nb, Mo or a combination
15 thereof;
- E is a fluoride, hydroxide or chloride anion;
- f is the molar fraction of the J04 oxyanion, generally comprised between 0.75 and
1.
The M1M2(J04)fE1-f electro-active material as defined above is preferably
20 phosphate-based. It may exhibit an ordered or modified olivine structure.
For a positive electrode, the EAC may also be sulfur or Li2S.
For a positive electrode , the EAC may also be a conversion-type materials such
as FeS2 or FeF2 or FeF3
For a negative electrode, the EAC may be selected in the group consisting of
25 graphitic carbons able to intercalate lithium. More details about this type of EAC
may be found in Carbon 2000, 38, 1031-1041. This type of EAC typically exist in
the form of powders, flakes, fibers or spheres (e.g. mesocarbon microbeads).
The EAC may also be: lithium metal; lithium alloy compositions (e.g. those
described in US 6,203,944 and in WO 00/03444); lithium titanates, generally
30 represented by formula Li4Tis012; these compounds are generally considered as
"zero-strain" insertion materials, having low level of physical expansion upon
taking up the mobile ions, i.e. Li+; lithium-silicon alloys, generally known as lithium
silicides with high Li/Si ratios, in particular lithium silicides of formula Li4_4Si and
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lithium-germanium alloys, including crystalline phases of formula Li4_4Ge. EAC may
also be composite materials based on carbonaceous material with silicon and/or
silicon oxide, notably graphite carbon/silicon and graphite/silicon oxide, wherein
the graphite carbon is composed of one or several carbons able to intercalate
5 lithium.
The ECM is typically selected in the group consisting of electro-conductive
carbonaceous materials and metal powders or fibers. The electron-conductive
carbonaceous materials may for instance be selected in the group consisting of
carbon blacks, carbon nanotubes, graphite, graphene and graphite fibers and
10 combinations thereof. Examples of carbon blacks include ketjen black and
acetylene black. The metal powders or fibers include nickel and aluminum
powders or fibers.
The lithium salt (LIS) may be selected in the group consisting of LiPFe, lithium
bis(trifluoromethanesulfonyl)imide , lithium bis(fluorosulfonyl)imide, LiB(C204)2,
15 LiAsFe, LiCI04, LiBF4, LiAI04, LiN03, LiCF3S03, LiN(S02CF3)2, LiN(S02C2Fs)2,
LiC(S02CF3)3, LiN(S03CF3)2, LiC4FgS03, LiCF3S03, LiAICI4, LiSbFe, LiF, LiBr,
LiCI, LiOH and lithium 2-trifluoromethyl-4,5-dicyanoimidazole.
The function of the polymeric binding material (P) is to hold together the
components of the composition. The polymeric binding material is usually inert. It
20 preferably should be also chemically stable and facilitate the electronic and ionic
transport. The polymeric binding material is well known in the art. Non-limitative
examples of polymeric binder materials include notably, vinylidenefluoride (VDF)based
(co)polymers, styrene-butadiene rubber (SBR), styrene-ethylene-butylenestyrene
(SEBS), carboxymethylcellulose (CMC), polyamideimide (PAl),
25 poly(tetrafluoroethylene) (PTFE) and poly(acrylonitrile) (PAN) (co)polymers.
The proportion of the solid material of the invention in the composition may be
between 0.1 wt% to 80 wt%, based on the total weight of the composition. In
particular, this proportion may be between 1.0 wt% to 60 wt%, more particularly
between 5 wt% to 30 wt%. The thickness of the electrode is not particularly limited
30 and should be adapted with respect to the energy and power required in the
application. For example, the thickness of the electrode may be between 0.01 mm
to 1.000 mm.
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The solid material of the invention may also be used in the preparation of a
separator. A separator is an ionically permeable membrane placed between the
anode and the cathode of a battery. Its function is to be permeable to the lithium
ions while blocking electrons and assuring the physical separation between the
5 electrodes.
The separator of the invention typically comprises at least:
- a solid material comprising Li, Zn, P and S elements and exhibiting at least peaks
at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/-
0.50 when analyzed by x-ray diffraction using CuKa radiation at 25°C, preferably a
1 0 solid material of formula (I) as follows:
Li4-2xZnxP2Ss (I)
wherein 0 < x :::; 1 ;
- optionally at least one polymeric binding material (P);
-optionally at least one metal salt, notably a lithium salt;
15 - optionally at least one plasticizer.
The electrode and the separator may be prepared using methods well-known to
the skilled person. This usually mixing the components in an appropriate solvent
and removing the solvent. For instance, the electrode may be prepared by the
process which comprises the following steps:
20 - a slurry comprising the components of composition and at least one solvent is
applied onto the metal substrate;
-the solvent is removed.
Usual techniques known to the skilled person are the following ones: coating and
calendaring, dry and wet extrusion, 30 printing, sintering of porous foam followed
25 by impregnation. Usual techniques of preparation of the electrode and of the
separator are provided in Journal of Power Sources, 2018 382, 160-175.
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The electrochemical devices, notably batteries such as solid state batteries
described herein, can be used for making or operating cars, computers, personal
digital assistants, mobile telephones, watches, camcorders, digital cameras,
thermometers, calculators, laptop BIOS, communication equipment or remote car
5 locks, and stationary applications such as energy storage devices for power
plants.
The electrochemical devices, notably batteries such as solid state batteries
described herein, can notably be used in motor vehicles, bicycles operated by
electric motor, robots, aircraft (for example unmanned aerial vehicles including
10 drones), ships or stationary energy storages. Preferred are mobile devices such as
are vehicles, for example automobiles, bicycles, aircraft, or water vehicles such as
boats or ships. Other examples of mobile devices are those which are portable, for
example computers, especially laptops, telephones or electrical power tools, for
example from the construction sector, especially drills, battery-driven screwdrivers
15 or battery-driven tackers.
20
Should the disclosure of any patents, patent applications, and publications which
are incorporated herein by reference conflict with the description of the present
application to the extent that it may render a term unclear, the present description
shall take precedence.
FIGURES
Figure 1: powder XRD pattern of samples of Examples 1-4 and 6. Circle highlight
ZnS contribution in Example 4.
Figure 2: powder XRD pattern of samples of Example 2 and Example 5. Stars
25 indicate diffraction peaks of LiZnPS4-type phase in Example 5.
EXPERIMENTAL PART
The examples below serve to illustrate the invention, but have no limiting
character.
30 X-Ray Diffraction
X-Ray Diffraction of the samples were collected using a Bruker 08 diffractometer
with Cu Ka radiation at RT (except example 1 that was collected with Co Ka
radiation at 25°C) The samples were sealed in a Be-equipped sample holder in an
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Ar filled glovebox prior to the experiment. The diffractions were collected in 28
range of 1 oo to 1 ooo in 13 hours. The lattice parameters were determined by fitting
the diffraction profiles using Full-Prof Suite.
5 Conductivity & Electrochemical Impedance Spectroscopy (EIS)
Before the impedance spectroscopy measurements, powder samples were coldpressed
at 530 MPa in an Ar filled glovebox. The pellets were then sandwiched
between pre-dried carbon paper electrodes, and then loaded into air-tight sample
holders. The AC impedance spectra were collected by using Biologic MTZ-35
1 0 frequency response analyser. During the measurements, the AC potential for
excitation was set at 50 mV for all the samples. The frequency range of the
measurement of the Example 1 was 0.01 Hz to 30 MHz, whereas a range of 0.1
Hz to 30 MHz was applied in the measurements of the Example 2, the Example 3,
the Example 4 and the Counter Example 5. The impedance measurements took
15 place at stabilized temperatures between 20°C and 60°C for the Example 1, -1 ooc
and sooc for the Example 2, -1 ooc and 70°C for the Example 3, ooc and sooc for
the Example 4 and ooc and sooc for the Example 5, in steps of 1 0°C. The ionic
conductivity values were obtained by fitting the data into equivalent circuit models
using ZView software. The slopes of the aT versus 1/T plots were used to
20 determine activation energy values.
Moisture Stability
Moisture stability was measured using a H2S sensor (Sensorcon Industrial Pro
from Mol ex) . H2S liberation kinetic was measured at 23°C with 30 mg of each
25 sample in a 10 L desiccator filled with ambient non-dried air (relative humidity
between 70% and 90%, non-controlled). Values showed (in ppm) by the sensor
are recorded every 20 seconds for 15 minutes and converted in number of moles
of H2S generated per liter of ambient air and gram of sample.
30 COUNTER EXAMPLE 1: Li4P2S6 synthesized via Solid State route
Li2S and P2Ss (both produced by Sigma Aldrich, ;::: 99 %), were used as starting
materials, mixed with mortar and pestle in an Ar filled glovebox. The resulting
powder was pelletized at 530 MPa with a 6 mm diameter die. The pellet vacuum
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sealed in a carbon coated quartz tube, then the tube was annealed at 750°C for 60
hours. After the annealing step, the tube was slowly cooled down to 25°C, and it
was opened in an Ar filled glovebox.
The XRD pattern shows a well-crystalline material, with XRD peaks (28 position
5 with Cu alpha wavelenght): at 16.8°, 2r, 32°, 32.4°. Indexation in the trigonal
space group P-31 m is possible and cell parameters are a= b= 6.08 A and c=6.60
A and the volume per formula atom is 211 A3/f.u.
Ionic conductivity at 60°C is 9*1 o-9 S/cm with an activation energy of 0.61 eV. Ionic
conductivity at room temperature was too low to be measured directly, around 1 o-9
10 S/cm.
H2S generation after 12 minutes was 54 1-Jmoi/Lairlgsample·
EXAMPLE 2: lb_33Zno.33P2Ss
Li2S, P2Ss (both produced by Sigma Aldrich, :::: 99 %), and ZnS (produced by Alfa
15 Aesar :::: 99 %) were used as starting materials. 2 g of total powder at the desired
molar ratio were put in a 45 ml Zr02 jar with 15 Zr02 balls (3 g/ball, 10 mm
diameter) in an Ar filled glovebox. The jar was sealed with scotch and parafilm to
prevent air exposure, then was taken out of the glovebox and was placed in
Fritzch Planetary Micro Mill Pulverisette 7. It was ball-milled with 510 RPM rotating
20 speed for 38 hours while employing 15 minute breaks in every 15 minutes of
milling, in order to prevent excessive heating of the jar. The jar was then moved in
an Ar filled glovebox to collect the powder. The resulting powder was pelletized at
530 MPa with a 6 mm diameter die. The pellet was vacuum sealed in a carbon
coated quartz tube, then the tube was annealed at 600°C for 36 hours. After the
25 annealing step, the tube was slowly cooled down to 25°C, and it was opened in an
Ar filled glovebox.
The XRD pattern shows a well-crystalline material, with XRD peaks at (28 position
with Cu alpha wavelenght): 13.4°, 16.9°, 27.1 °, 32.1 °, 32.6°. Indexation in the
trigonal space group P-31 m is possible, cell parameters are a= b= 6.06A and
30 c=6.59A and the volume per formula atom is 209 A3/f.u.
No extra phase is detected, proving that Zn is inserted in the structure.
Ionic conductivity at 25°C is 1.1 o-6 S/cm with an activation energy of 0.51 eV.
H2S generation after 12 minutes was 14 1-Jmoi/Lairlgsample·
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EXAMPLE 3: lbZno.sP2Ss
Li2S, P2Ss (both produced by Sigma Aldrich, :::: 99 %) and ZnS (produced by Alfa
Aesar:::: 99 %) were used as starting materials. 2 g of total powder at the desired
5 molar ratio were put in a 45 ml Zr02 jar with 12 Zr02 balls (3 g/ball, 10 mm
diameter) in an Ar filled glovebox. The jar was sealed with scotch and parafilm to
prevent air exposure, then was taken out of the glovebox and was placed in
Fritsch Planetary Micro Mill Pulverisette 7. It was ball-milled with 510 RPM rotating
speed for 38 hours while employing 15 minute breaks in every 15 minutes of
10 milling, in order to prevent excessive heating of the jar. The jar was then moved in
an Ar filled glovebox to collect the powder. The resulting powder was pelletized at
530 MPa with a 6 mm diameter die. The pellet vacuum sealed in a carbon coated
quartz tube, then the tube was annealed at 600°C for 36 hours. After the annealing
step, the tube was slowly cooled down to 25°C, and it was opened in an Ar filled
15 glovebox.
The XRD pattern shows a well-crystalline material, with XRD peaks at (28 position
with Cu alpha wavelenght): 13.4°, 16.9°, 2r, 32°, 32.5°. Indexation in the trigonal
space group P-31 m is possible , cell parameters are a= b= 6.06A and c=6.59A
and the volume per formula atom is 210 A3/f.u.
20 No extra phase is detected, proving that Zn is inserted in the new structure.
Ionic conductivity at 20°C is 3.1 o-7 S/cm with an activation energy of 0.51 eV.
H2S generation after 12 minutes was 1 IJmoi/Lairlgsample.·
EXAMPLE 4: Li2.sssZno.sssP2Ss
25 Li2S, P2Ss (both produced by Sigma Aldrich, :::: 99 %) and ZnS (produced by Alfa
Aesar:::: 99 %) were used as starting materials. 2 g of total powder at the desired
molar ratio were put in a 45 ml Zr02 jar with 15 Zr02 balls (3 g/ball, 10 mm
diameter) in an Ar filled glovebox. The jar was sealed with scotch and parafilm to
prevent air exposure, then was taken out of the glovebox and was placed in
30 Fritsch Planetary Micro Mill Pulverisette 7. It was ball-milled with 510 RPM rotating
speed for 38 hours while employing 15 minute breaks in every 15 minutes of
milling, in order to prevent excessive heating of the jar. The jar was then moved in
an Ar filled glovebox to collect the powder. The resulting powder was pelletized at
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530 MPa with a 6 mm diameter die. The pellet vacuum sealed in a carbon coated
quartz tube, then the tube was annealed at 600°C for 36 hours. After the annealing
step, the tube was slowly cooled down to 25°C, and it was opened in an Ar filled
glovebox.
5 The XRD pattern shows a well-crystalline material, with XRD peaks at (28 position
with Cu alpha wavelenght): 13.4°, 16.9°, 2r, 32.1 °. 32.5°. Indexation in the
trigonal space group P-31 m is possible, cell parameters are a= b= 6.06A and
c=6.59A and the volume per formula atom is 209 A3/f.u.
Small amount of ZnS extra phase is detected, proving that large part of Zn is
10 inserted in the structure but that solubility limit is probably reached.
Ionic conductivity at 20°C is 5.1 o-7 S/cm with an activation energy of 0.56 eV.
H2S generation after 12 minutes was 0 IJmoi/Lairlgsample·
COUNTER EXAMPLE 5: lb_33Zno.33P2Ss at 350°C
15 Li2S, P2Ss (both produced by Sigma Aldrich, :::: 99 %?) and ZnS (produced by Alfa
Aesar) were used as starting materials. 2 g of total powder at the desired molar
ratio were put in a 45 ml Zr02 jar with 15 Zr02 balls (3 g/ball, 10 mm diameter) in
an Ar filled glovebox. The jar was sealed with scotch and parafilm to prevent air
exposure, then was taken out of the glovebox and was placed in Fritsch Planetary
20 Micro Mill Pulverisette 7. It was ball-milled with 510 RPM rotating speed for 38
hours while employing 15 minute breaks in every 15 minutes of milling, in order to
prevent excessive heating of the jar. The jar was then moved in an Ar filled
glovebox to collect the powder. The resulting powder was pelletized at 530 MPa
with a 6 mm diameter die. The pellet vacuum sealed in a carbon coated quartz
25 tube, then the tube was annealed at 350°C for 36 hours. After the annealing step,
the tube was slowly cooled down to 25°C, and it was opened in an Ar filled
glovebox.

CLAIMS
PCT/EP2021/063911
1. A solid material comprising Li, Zn, P and S elements and exhibiting at least
peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°,
5 32.6°+/- 0.5° when analyzed by x-ray diffraction using CuKa radiation at 25°C.
10
15
2. Solid material according to claim 1 wherein solid material has peaks at position
of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when
analyzed by x-ray diffraction using CuKa radiation at 25°C.
3. Solid material according to claim 1 or 2 wherein solid material is of general
formula (I) as follows:
Li4-2xZnxP2Ss (I)
wherein 0 < x :::; 1, preferably xis chosen from 0.2 to 0.7.
4. Solid material according to anyone of claims 1 to 3 wherein x is chosen from
0.33 to 0.5.
5. Solid material according to anyone of claims 1 to 4 wherein it is in powder form
20 with a distribution of particle diameters having a 050 comprised between 0.05 1-1m
and 10 1-Jm.
6. Solid material according to anyone of claims 1 to 5 wherein it chosen in the
group consisting of: Li3.sZno.1 P2Se, Li3.eZno.2P2Se, Li3.sZno.2sP2Se, Li3.33Zno.33P2Se,
25 Li3.2Zno.4P2Se, Li3Zno.sP2Se, and Li2.eeeZno.eeeP2Se.
7. A method for producing a solid material according to anyone of claims 1 to 6
comprising at least bringing at least lithium sulfide, phosphorous sulfide and zinc
compound, optionally in one or more solvents, then proceeding with a heat
30 treatment at a temperature in the range of from 375°C to 900°C, under an inert
atmosphere, thereby forming the solid material.
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8. A process for the preparation of a solid material comprising Li, Zn, P and S
elements and exhibiting at least peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°,
27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when analyzed by x-ray diffraction using
CuKa radiation at 25°C, said process comprising at least the process steps of:
5 a) obtaining a composition by admixing stoichiometric amounts of lithium sulfide,
phosphorous sulfide, and a zinc compound, optionally in one or more solvents,
under an inert atmosphere;
b) applying a mechanical treatment to the composition obtained in step a);
c) optionally removing at least a portion of the one or more solvents from the
10 composition obtained on step b), so that to obtain a solid residue;
d) heating the obtained residue obtained in step c) at a temperature in the range of
from 370°C to 900°C, under an inert atmosphere, thereby forming the solid
material; and
e) optionally treating the solid material obtained in step d) to the desired particle
15 size distribution.
9. A process for the preparation of a solid material according to general formula (I)
as follows:
Li4-2xZnxP2Ss (I)
20 wherein 0 < x :::; 1, preferably x is chosen from 0.2 to 0. 7;
said process comprising at least the process steps of:
a) obtaining a composition by admixing stoichiometric amounts of lithium sulfide,
phosphorous sulfide, and a zinc compound in order to obtain Li4-2xZnxP2S7,
optionally in one or more solvents, under an inert atmosphere;
25 b) applying a mechanical treatment to the composition obtained in step a);
c) optionally removing at least a portion of the one or more solvents from the
composition obtained on step b), so that to obtain a solid residue;
d) heating the obtained residue obtained in step c) at a temperature in the range of
from 375°C to 900°C, under an inert atmosphere, thereby forming the solid
30 material; and
e) optionally treating the solid material obtained in step d) to the desired particle
size distribution.
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10. Process according to claim 8 or 9 wherein the zinc compound is chosen in the
group consisting of ZnS and Zn.
5 11. Process according to anyone of claims 8 to 10 wherein lithium sulfide is Li2S,
phosphorous sulfide is P2Ss, and zinc compound is ZnS.
12. Process according to anyone of claims 8 to 10 wherein the solvent is selected
in the group consisting of alkanols, notably having 1 to 6 carbon atoms, such as
10 methanol, ethanol, propanol and butanol; carbonates, such as dimethyl carbonate;
acetates, such as ethyl acetate; ethers, such as dimethyl ether, tetrahydrofuran;
organic nitriles, such as acetonitrile; aliphatic hydrocarbons, such as hexane,
pentane, 2-ethylhexane, heptane, decane, and cyclohexane; and aromatic
hydrocarbons, such as xylene and toluene.
15
13. Process according to anyone of claims 8 to 12 wherein in step b) the
mechanical treatment is performed by wet or dry milling.
14. Process according to anyone of claims 8 to 13 wherein the heat treatment is
20 carried out in step d) at a temperature in the range of from 400°C to 700°C,
preferably from 550°C to 650°C.
25
30
15. A solid material susceptible to be obtained by the process according to anyone
of claims 8 to 14.
16. Use of a solid material comprising Li, Zn, P and S elements and exhibiting at
least peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°,
32.6°+/- 0.5° when analyzed by x-ray diffraction using CuKa radiation at 25°C,
preferably a solid material of formula (I) as follows:
wherein 0 < x :::; 1 ;
as solid electrolyte.
Li4-2xZnxP2Ss (I)
5
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17. A solid electrolyte comprising at least a solid material comprising Li, Zn, P and
S elements and exhibiting at least peaks at position of: 13.4° +/- 0.5°, 16.9°+/-
0.50, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when analyzed by x-ray diffraction
using CuKa radiation at 25°C, preferably a solid material of formula (I) as follows:
Li4-2xZnxP2Ss (I)
wherein 0 < x :::; 1 .
18. An electrochemical device comprising at least a solid electrolyte comprising at
least a solid material comprising Li, Zn, P and S elements and exhibiting at least
10 peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°,
32.6°+/- 0.5° when analyzed by x-ray diffraction using CuKa radiation at 25°C,
preferably a solid material of formula (I) as follows:
15
Li4-2xZnxP2Ss (I)
wherein 0 < x :::; 1 .
19. A solid state battery comprising at least a solid electrolyte comprising at least a
solid material comprising Li, Zn, P and S elements and exhibiting at least peaks at
position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/- 0.5°
when analyzed by x-ray diffraction using CuKa radiation at 25°C, preferably a solid
20 material of formula (I) as follows:
wherein 0 < x :::; 1 .
20. A vehicle comprising at least a solid state battery comprising at least a solid
25 electrolyte comprising at least a solid material comprising Li, Zn, P and S elements
and exhibiting at least peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/-
0.50, 32.1 °+/- 0.5°, 32.6°+/- 0.5° when analyzed by x-ray diffraction using CuKa
radiation at 25°C, preferably a solid material of formula (I) as follows:
Li4-2xZnxP2Ss (I)
30 wherein 0 < x :::; 1 .
21. An electrode comprising at least:
- a metal substrate;
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- directly adhered onto said metal substrate, at least one layer made of a
composition comprising:
(i) a solid material comprising Li, Zn, P and S elements and exhibiting at least
peaks at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°,
5 32.6°+/- 0.5° when analyzed by x-ray diffraction using CuKa radiation at 25°C,
preferably a solid material of formula (I) as follows:
Li4-2xZnxP2Ss (I)
wherein 0 < x :::; 1 ;
(ii) at least one electro-active compound (EAC);
10 (iii) optionally at least one lithium ion-conducting material (LiCM) other than the
solid material of the invention;
15
(iv) optionally at least one electro-conductive material (ECM);
(v) optionally a lithium salt (LIS);
(vi) optionally at least one polymeric binding material (P).
22. A separator comprising at least:
- a solid material comprising Li, Zn, P and S elements and exhibiting at least peaks
at position of: 13.4° +/- 0.5°, 16.9°+/- 0.5°, 27.1 °+/- 0.5°, 32.1 °+/- 0.5°, 32.6°+/-
0.50 when analyzed by x-ray diffraction using CuKa radiation at 25°C, preferably a
20 solid material of formula (I) as follows:
Li4-2xZnxP2Ss (I)
wherein 0 < x :::; 1 ;
- optionally at least one polymeric binding material (P);
-optionally at least one metal salt, notably a lithium salt;
25 - optionally at least one plasticizer.