PRIOR ART
Lithium batteries are used to power portable electronics and electric vehicles
15 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
solvents are flammable. Lithium dendrites forming and passing through the liquid
electrolyte medium can cause short circuit and produce heat, which result in
20 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
electrolyte having a higher degree of safety is expected as an electrolyte for a
next-generation lithium battery.
25 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
battery.
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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
eliminates the necessity of a high temperature assembly step. Elimination of the
5 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
having a high conductivity for lithium ions. An important class of such solid
electrolytes are materials of the composition LiaPSsX (X = Cl, Br) which have an
10 argyrodite structure. Argyrodites have long been known and are derived from
argyrodite AgaGeSe, which was described for the first time in 1886 by C. Winkler
and the analysis of which led to the discovery of germanium. The argyrodite family
consists of more than 100 crystalline solids and includes, for example, those solidstate
compounds in which the silver is replaced by copper, the germanium by
15 gallium or phosphorus and the sulfur by selenium. Thus, Nitsche, Kuhs, Krebs,
Evain, Boucher, Pfitzner and Nilges describe, inter alia, compounds such as
CugGaSe, Ag7PSee and CuaGaSsCI, the solid-state structures of which are derived
from argyrodite.
Most of the lithium argyrodites, and in particular most of the LiaPSsCI, as reported
20 in the literature, are prepared via a dry or wet mechanochemical route.
25
There is however a need for new solid sulfide electrolytes having optimized
performances, such as higher ionic conductivity and lower activation energy,
without compromising other 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 LiaPSsCI
materials may be obtained by using copper dopant. The new LiCuPSX solid
30 materials of the invention also exhibits at least similar chemical and mechanical
stability and processability like those conventional lithium argyrodites. 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
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materials of the invention exhibit a lower amount of raw materials impurity, such as
Li2S and LiCI impurity. Solid materials of the invention exhibit also a lower amount
of undesired phases, such as Gamma-Li3PS4.
The present invention refers then to a solid material according to general formula
5 (I) as follows:
Lis-x-2yCuxPSs-yX (I)
wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
10 - 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25.
The invention also concerns a method for producing a solid material according to
general formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
wherein:
15 -X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25;
comprising at least bringing at least lithium sulfide, phosphorous sulfide, halogen
compound and a copper compound, optionally in one or more solvents.
20 The invention also refers to a process for the preparation of a solid material
according to general formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
25 - 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25;
said process comprising at least the process steps of:
a) obtaining a composition by admixing stoichiometric amounts of lithium sulfide,
phosphorous sulfide, halogen compound and a copper compound, optionally in
30 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;
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d) heating the obtained residue obtained in step c) at a temperature in the range of
from 1 oooc to 700°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
5 size distribution.
The invention furthermore concerns a solid material susceptible to be obtained by
said first process.
Solid materials of the invention may also be produced by a full solution method.
Notably the invention also refers to a process for the preparation of a solid material
10 according to general formula (I), as follows:
Lis-x-2yCuxP55-yX (I)
wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
15 - 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25;
said process comprising at least the process steps of:
a') obtaining a solution by admixing stoichiometric amounts of lithium compounds,
sulfide compounds, phosphorous compounds, halogen compound and a copper
compound, in one or more solvents, under an inert atmosphere;
20 b') removing at least a portion of the one or more solvents from the composition as
obtained in step a'), so that to obtain a solid material; preferably at a temperature
in the range of from 30°C to 200°C, under an inert atmosphere;
c') optionally heating the solid material as obtained in step b'), at a temperature in
the range of from 1 oooc to 700°C, under an inert atmosphere; and
25 d') optionally treating the solid material obtained in step c') to the desired particle
size distribution.
The invention furthermore concerns a solid material susceptible to be obtained by
said second process.
The invention also refers to the use of a solid material of formula (I) as follows:
30 Lis-x-2yCuxP55-yX (I)
wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
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- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25;
as solid electrolyte.
PCT/EP2021/057020
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The invention also refers to a solid electrolyte comprising at least a solid material
of formula (I) as follows:
5 Lis-x-2yCuxPSs-yX (I)
wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25.
10 The invention also concerns an electrochemical device comprising at least a solid
electrolyte comprising at least a solid material of formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
15 - 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25.
The invention also refers to a solid state battery comprising at least a solid
electrolyte comprising at least a solid material of formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
20 wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25.
The present invention also concerns a vehicle comprising at least a solid state
25 battery comprising at least a solid electrolyte comprising at least a solid material of
formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
30 - 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25.
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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
10 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.
As used herein, the term "argyrodite," or "argyrodite crystal" refers to a crystal
structure or crystal bonding arrangement. This crystal structure or bonding
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arrangement is based on the crystal structure for the natural mineral, argyrodite,
which is a silver germanium sulfide mineral characterized by the chemical formula
AgaGeSa. This crystal structure is also exemplified by the isomorphous argyrodite
mineral, AgsSnSe.
5 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
powder pattern of intensity v. degrees (28) which have a peak intensity
10 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
intensity.
15 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.,
single or "disposable" use) battery, or a secondary (i.e., rechargeable) battery.
20 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.
During a discharge cycle in a Li-secondary battery, Li ions migrate towards the
25 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
including sports utility vehicles (SUV), buses, trucks, various commercial vehicles,
30 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
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vehicle that has two or more different sources of power, for example both
gasoline-powered and electric-powered vehicles.
DETAILED INVENTION
5 The invention then relates to a solid material according to general formula (I)
Lis-x-2yCuxPSs-yX (I)
wherein:
-X is halogen, preferably selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
10 - 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25.
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
averaged over all phases present in the solid material.
15 X is preferably Cl and preferably 0.02 :::; x :::; 0.8, more preferably 0.03 :::; x :::; 0.6,
particularly 0.03:::; x:::; 0.06. More preferably xis 0.01, 0.02, 0.03, 0.04, 0.05, 0.06,
0.07, 0.08, 0.09 and 0.1 or any range made from these values. More preferably y
is 0, 0.1, 0.2, 0.3, 0.4 and 0.5 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. The
crystallized part of the solid material may comprise only one crystal structure or
may comprise a plurality of crystal structures. The crystallization degree of the
solid material (the crystallization degree of a crystal structure of which the ionic
conductivity is higher than that of an amorphous body) is preferably comprised
25 from 80% to 1 00%.
The degree of crystallization may be measured by means of an NMR spectrum
apparatus. Specifically, the solid 31P-NMR spectrum of the solid material is
measured, and for the resulting spectrum, the resonance line observed at 70 to
120 ppm is separated into a Gaussian curve by using nonlinear least-squares
30 method, and the ratio of areas of each curve is obtained.
Solid material of the invention preferably comprises a fraction consisting of
crystalline phases, wherein one of said crystalline phases has the argyrodite
structure. Preferably said crystalline phase having the argyrodite phase makes
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from 90 to 100% of the total weight of the fraction consisting of crystalline phases.
Such a fraction may be measured by X-Ray Diffraction by mean of Rietveld
refinement of the total diffractogram. This refinement can be done with FuiiProf
software by using multiphase refinement option.
5 Solid material of the invention may comprise structural units PS4
3
- and structural
units P04
3
-, wherein preferably the ratio between the amount of structural units
PS4
3
- and the amount of structural units P04
3
- is in the range from 1000:1 to 9:1.
Solid material of the invention may comprise at least peaks at position of:
15,65°+/- 0,5°, 25,53°+/- 0,5°, 30, 16°+/- 0,5°, and 31 ,52°+/- 0,5° (28) when
10 analyzed by x-ray diffraction using CuKa radiation at 25°C.
The cristallographic space group of the solid material of the present invention is
preferably space group 226 (F43m). In this space group, cell parameters of the
solid materials of the present invention may range from 9,680 Angstrom to 9,840
Angstrom, as measured by x-ray diffraction using CuKa radiation at 25°C, and
15 further calculated with a dedicated software, such as Fullprof software, using a
refinement method such as Rietveld and Le Bail refinement.
Preferably solid materials of formula (I) according to the present invention may be
as follows:
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X y Li Cu p s Cl
0.015 0 5.99 0.015 1 5 1
0.03 0 5.97 0.03 1 5 1
0.06 0 5.94 0.06 1 5 1
0.3 0 5.70 0.3 1 5 1
0.6 0 5.40 0.6 1 5 1
1 0 5.00 1 1 5 1
1.3 0 4.70 1.3 1 5 1
1.5 0 4.50 1.5 1 5 1
0.015 0.1 5.79 0.015 1 4.9 1
0.03 0.1 5.77 0.03 1 4.9 1
0.06 0.1 5.74 0.06 1 4.9 1
0.3 0.1 5.50 0.3 1 4.9 1
0.6 0.1 5.20 0.6 1 4.9 1
1 0.1 4.80 1 1 4.9 1
1.3 0.1 4.50 1.3 1 4.9 1
1.5 0.1 4.30 1.5 1 4.9 1
0.015 0.2 5.59 0.015 1 4.8 1
0.03 0.2 5.57 0.03 1 4.8 1
0.06 0.2 5.54 0.06 1 4.8 1
0.3 0.2 5.30 0.3 1 4.8 1
0.6 0.2 5.00 0.6 1 4.8 1
1 0.2 4.60 1 1 4.8 1
1.3 0.2 4.30 1.3 1 4.8 1
1.5 0.2 4.10 1.5 1 4.8 1
0.015 0.25 5.49 0.015 1 4.75 1
0.03 0.25 5.47 0.03 1 4.75 1
0.06 0.25 5,44 0.06 1 4.75 1
0.3 0.25 5.20 0.3 1 4.75 1
0.6 0.25 4.90 0.6 1 4.75 1
1 0.25 4.50 1 1 4.75 1
1.3 0.25 4.20 1.3 1 4.75 1
1.5 0.25 4.00 1.5 1 4.75 1
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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).
5 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
10 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,
15 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.
20 050 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 refers to a method for producing a solid material according to
25 general formula (I) comprising at least bringing at least lithium sulfide,
phosphorous sulfide, halogen compound and a copper compound, optionally in
one or more solvents. One or more lithium sulfide, phosphorous sulfide, halogen
compound and a copper compound may be used.
Notably, the present invention concerns also a method for producing a solid
30 material according to general formula (I) comprising at least reacting at least
lithium sulfide, phosphorous sulfide, halogen compound and a copper compound,
optionally in one or more solvents. One or more lithium sulfide, phosphorous
sulfide, halogen compound and a copper compound may be used.
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Solid materials of the invention may be produced by any methods used in the prior
art known for producing a sulfide-based glass solid electrolyte, 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
5 more solvents.
The invention then 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:
10 a) obtaining a composition by admixing stoichiometric amounts of lithium sulfide,
phosphorous sulfide, halogen compound and a copper 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
15 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 1 oooc to 700°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
20 size distribution.
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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
5 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
10 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
15 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.
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).
20 The composition ratio of each element can be controlled by adjusting the amount
of the raw material compound when the solid material is produced. The precursors
and their molar ratio are selected according to the target stoichiometry. The target
stoichiometry defines the ratio between the elements Li, Cu, P, S and M, which is
obtainable from the applied amounts of the precursors under the condition of
25 complete conversion without side 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.
30 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
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certain preferred aspects, phosphorus sulfide may consist of sulfur atoms and
phosphorus atoms. Non-limiting exemplary phosphorus sulfide may include, but
not limited to, P2Ss, P4S3, P4S1o, P4S4, P4Ss, P4Se, P4S7, P4Ss, and P4Sg.
Halogen compound refers to a compound including one or more of halogen atoms
5 such as F, Cl, Br, or I via chemical bond (e.g., ionic bond or covalent bond) to the
other atoms constituting the compound. In certain preferred aspect, the halogen
compound may include one or more of F, Cl, Br, I, or combinations thereof and
one or more metal atoms. In other preferred aspect, the halogen compound may
include one or more of F, Cl, Br, I, or combinations thereof and one or more non-
10 metal atoms. Non-limiting examples may suitably include metal halide such as LiF,
LiBr, LiCI, Lil, NaF, NaBr, NaCI, Nal, KaF, KBr, KCI, Kl, and the like. In certain
preferred aspect, the halogen compound suitably for the use in a solid electrolyte
in all-solid Li-ion battery may include one or more halogen atoms and Li.
Preferably, the halogen compound may be selected from the group consisting of
15 lithium bromide (LiBr), lithium chloride (LiCI), lithium iodide (Lil) and combinations
thereof.
Copper compound refers to a compound including one or more of Cu atoms via
chemical bond (e.g., ionic bond or covalent bond) to the other atoms constituting
the compound. In another aspect, copper compound can be metallic copper. In
20 certain preferred aspect, the copper compound may include one or more Cu
atoms one or more non-metal atoms, such as S, Cl or Br. Copper compounds are
preferably chosen in the group consisting of: CuS, Cu2S, Cu2-xS (wherein x is
comprised between 0 and 1, notably x=0,06 (djurleite), x=O, 1, x=0,2 (digenite)) and
CuCI2. Copper compound of the invention may also be a blend of metallic copper
25 and elementary sulfur.
Preferably, the solid material of the invention is made by using at least the
precursors as follows: Li2S, P2Ss, LiCI and Cu2S. Lithium sulfide is then Li2S,
phosphorous sulfide is then P2Ss, halogen compound is then LiCI, and copper
compound is then Cu2S.
30 Preferably, lithium sulfide, phosphorous sulfide, halogen compound and a copper
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, halogen compound and copper compound.
Said solvent may also substantially suspend, dissolve or otherwise admix the
5 above described components, e.g., lithium sulfide, phosphorus sulfide, halogen
compound and copper 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
10 rather dissolved, partially dissolved or under a form of a slurry.(ie. component(s)
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
15 butanol; carbonates, such as dimethyl carbonate; acetates, such as ethyl acetate;
ethers, such as dimethyl ether; organic nitriles, such as acetonitrile; aliphatic
hydrocarbons, such as hexane, pentane, 2-ethylhexane, heptane, decane, and
cyclohexane; and aromatic hydrocarbons, such as tetrahydrofuran, xylene and
toluene.
20 It is understood that references herein to "a solvent" includes one or more mixed
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
25 75 wt% of the powder mixture and an amount of 25 wt% to 75 wt% of the solvent,
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.
30 The temperature of step a) in presence of solvent is preferably between the fusion
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
10 lithium argyrodites.
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, halogen compound and
copper 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
20 temperature of the selected solvent and ebullition temperature of the selected
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.
25 Mechanical treatment to the composition in step b) may also be performed by
stirring, notably by using well known techniques in the art, such as by using
standard powder or slurry mixers.
30
Usually a paste or a blend of paste and liquid solvent may be obtained at the end
of step b).
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 1 oooc to
700°C, preferably from 250°C to 600°C, notably for a duration of 1 minute to 1 00
hours, preferably from 30 minutes to 20 hours. Heat treatment may start directly at
high temperature or via a ramp of temperature at a rate comprised between
25 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
dry Argon (dry may refer to a gas with less than 800ppm of liquid and airborne
30 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.
10 In step e), it is possible to treat the solid material to the desired particle size
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
15 by means of dynamic light scattering or image analysis.
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
20 100.
The invention then 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:
25 a') obtaining a solution by admixing stoichiometric amounts of lithium compounds,
sulfide compounds, phosphorous compounds, halogen compound and a copper
compound, in one or more solvents, under an inert atmosphere;
b') removing at least a portion of the one or more solvents from the composition as
obtained in step a'), so that to obtain a solid material;
30 c') optionally heating the solid material as obtained in step b'), at a temperature in
the range of from 1 oooc to 700°C, under an inert atmosphere; and
d') optionally treating the solid material obtained in step c') to the desired particle
size distribution.
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Various features of step a') are basically similar to those of step a), such as for
instance with respect to precursors and solvent. Preferably temperature in step a)
ranges from -200°C to 1 00°C, preferably from -200°C to 1 0°C.
Features in the removal of solvent as mentioned in step b') may be similar to those
5 ones as expressed in step c). Preferably in step b'), temperature is in the range of
from 30°C to 200°C, under an inert atmosphere, and preferably under a pressure
0.0001 Pa to 100 MPa.
Heating of step c') may be carried out with features as expressed in step d).
Preferably at a temperature in the range of from 1 oooc to 700°C, under an inert
10 atmosphere and preferably under a pressure 0.0001 Pa to 100 MPa.
Features of treating the solid material as mentioned in step d') may be similar to
those ones as expressed in step e).
The invention also refers to a solid material of formula (I) as solid electrolyte, as
15 well as a solid electrolyte comprising at least a solid material of formula (I).
Said solid electrolytes comprises then at least a solid material of formula (I) and
optionally an other solid electrolyte, such as a lithium argyrodites, lithium
thiophosphates, such as glass or glass ceramics Li3PS4, Li7PS11, and lithium
conducting oxides such as lithium stuffed garnets Li7la3Zr2012 (LLZO), sulfide.
20 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
electrolyte comprising at least a solid material of formula (I).
25 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
and separator.
Herein preferably the solid electrolyte is a component of a solid structure for an
30 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
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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
5 called the cathode. The separator electronically separates a cathode and an
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,
10 metallic lithium, silicon compounds such as Si, SiOx, lithium titanates such as
Li4 Tis012 or a metal alloy comprising lithium as the anode active material such as
Sn.

CLAIMS
1. A solid material according to general formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
PCT/EP2021/057020
5 wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25.
10 2. Solid material according to claim 1 wherein X is Cl.
3. Solid material according to claim 1 or 2 wherein 0.02:::; x:::; 0.8.
4. Solid material according to anyone of claims 1 to 3 wherein the crystallization
15 degree of the solid material is comprised from 80% to 100%.
5. Solid material according to anyone of claims 1 to 4 wherein the solid material
comprises at least peaks at position of: 15,65°+/- 0,5°, 25,53°+/- 0,5°, 30, 16°+/-
0,50, and 31 ,52°+/- 0,5° (28) when analyzed by x-ray diffraction using CuKa
20 radiation at 25°C.
25
6. Solid material according to anyone of claims 1 to 5 wherein it is in powder form
with a distribution of particle diameters having a 050 comprised between 0.05 1-1m
and 10 1-Jm.
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, halogen
compound and a copper compound, optionally in one or more solvents.
30 8. A process for the preparation of a solid material according to anyone of claims 1
to 6 comprising at least the process steps of:
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a) obtaining a composition by admixing stoichiometric amounts of lithium sulfide,
phosphorous sulfide, halogen compound and a copper compound, optionally in
one or more solvents, under an inert atmosphere;
b) applying a mechanical treatment to the composition obtained in step a);
5 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 1 oooc to 700°C, under an inert atmosphere, thereby forming the solid
material; and
10 e) optionally treating the solid material obtained in step d) to the desired particle
size distribution.
9. Process according to claim 8 wherein the copper compound is chosen in the
group consisting of: CuS, Cu2S, Cu2-xS (wherein x is comprised between 0 and 1,
15 notably x=0,06, x=O, 1, x=0,2) and CuCI2.
10. Process according to claim 8 or 9 wherein lithium sulfide is Li2S, phosphorous
sulfide is P2Ss, halogen compound is LiCI, and copper compound is Cu2S.
20 11. Process according to anyone of claims 8 to 1 0 wherein the solvent is 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; ethers, such as dimethyl ether; organic nitriles,
such as acetonitrile; aliphatic hydrocarbons, such as hexane, pentane, 2-
25 ethylhexane, heptane, decane, and cyclohexane; and aromatic hydrocarbons,
such as tetrahydrofuran, xylene and toluene.
30
12. Process according to anyone of claims 8 to 11 wherein in step b) the
mechanical treatment is performed by wet or dry milling.
13. A solid material susceptible to be obtained by the process according to anyone
of claims 8 to 12.
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14. A process for the preparation of a solid material according to anyone of claims
1 to 6, said process comprising at least the process steps of:
a') obtaining a solution by admixing stoichiometric amounts of lithium compounds,
sulfide compounds, phosphorous compounds, halogen compound and a copper
5 compound, in one or more solvents, under an inert atmosphere;
b') removing at least a portion of the one or more solvents from the composition as
obtained in step a'), so that to obtain a solid material;
c') optionally heating the solid material as obtained in step b'), at a temperature in
the range of from 1 oooc to 700°C, under an inert atmosphere; and
10 d') optionally treating the solid material obtained in step c') to the desired particle
size distribution.
15
15. A solid material susceptible to be obtained by the process according to claim
14.
16. Use of a solid material of formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
20 - 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25;
as solid electrolyte.
17. A solid electrolyte comprising at least a solid material of formula (I) as follows:
25 Lis-x-2yCuxPSs-yX (I)
30
wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25.
18. An electrochemical device comprising at least a solid electrolyte comprising at
least a solid material of formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
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wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25.
5
19. A solid state battery comprising at least a solid electrolyte comprising at least a
solid material of formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
wherein:
10 -X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25.
20. A vehicle comprising at least a solid state battery comprising at least a solid
15 electrolyte comprising at least a solid material of formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
20 - 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25.
21. An electrode comprising at least:
- a metal substrate;
- directly adhered onto said metal substrate, at least one layer made of a
25 composition comprising:
(i) a solid material of formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
30 - 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25;
(ii) at least one electro-active compound (EAC);
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(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);
5 (vi) optionally at least one polymeric binding material (P).
22. A separator comprising at least:
- a solid material of formula (I) as follows:
Lis-x-2yCuxPSs-yX (I)
10 wherein:
-X is selected from the group consisting of: F, Cl, I and Br;
- 0.005:::; x:::; 5; preferably 0.015:::; x:::; 1.5; and
- 0:::; y:::; 0.5, preferably 0:::; y:::; 0.25;
- optionally at least one polymeric binding material (P);
15 -optionally at least one metal salt, notably a lithium salt;
- optionally at least one plasticizer.