Title of invention: lithium metal battery
Technical field
[One]
The present invention relates to a lithium metal battery comprising a composite solid electrolyte membrane.
[2]
This application is an application for claiming priority for Korean Patent Application No. 10-2018-0035292 filed on March 27, 2018, and all contents disclosed in the specification and drawings of the application are incorporated herein by reference.
Background
[3]
Recently, interest in energy storage technology is increasing. As the fields of application to mobile phones, camcorders, notebook PCs, and even electric vehicles are expanded, efforts for research and development of electrochemical devices are increasingly being materialized. Electrochemical devices are the field that is receiving the most attention in this respect, and the development of secondary batteries capable of charging and discharging among them has become the focus of interest. It is proceeding with research and development on the design of and battery.
[4]
Among the currently applied secondary batteries, the lithium secondary battery developed in the early 1990s has the advantage of having a higher operating voltage and significantly higher energy density than conventional batteries such as Ni-MH, Ni-Cd, and sulfuric acid-lead batteries using aqueous electrolyte solutions. Is in the limelight.
[5]
Among these, a lithium secondary battery using a liquid electrolyte has a structure in which the positive electrode and the negative electrode are partitioned by a separator, so if the separator is damaged by deformation or external shock, a short circuit may occur, which may lead to a risk of overheating or explosion. Therefore, the development of a solid electrolyte that can secure safety in the field of lithium secondary batteries is an important task.
[6]
The lithium secondary battery using a solid electrolyte has advantages in that the safety of the battery is increased, the leakage of the electrolyte solution can be prevented, so that the reliability of the battery is improved, and it is easy to manufacture a thin-type battery. In particular, when lithium metal is used as a negative electrode, energy density can be improved, and accordingly, it is expected to be applied to high-capacity secondary batteries for electric vehicles as well as small secondary batteries.
[7]
On the other hand, in the case of a battery to which a solid electrolyte is applied, since both the electrode and the solid electrolyte membrane are in a solid state and there is no liquid electrolyte, a void without ion conductivity, that is, a dead space, occurs at the interface between the electrode and the solid electrolyte membrane. There is.
[8]
In particular, when the electrode surface is uneven due to the shape of the electrode active material, aggregation of the conductive material, or lifting of the binder polymer, more dead space occurs, resulting in increased resistance between the electrode and the solid electrolyte membrane, which adversely affects the life performance of the battery. Can give.
[9]
In order to solve this problem, there have been attempts to fill the interface between the electrode and the solid electrolyte membrane by adding a liquid ion conductive material (or electrolyte) to a battery using a solid electrolyte. However, in order to use a liquid substance, the injection process is performed after assembly of the electrode assembly, and in this case, there is a disadvantage that an excessive amount must be injected in order for the liquid substance to exist between the interface of the solid electrolyte membrane and the electrode. There is a problem that the material softens the solid electrolyte membrane.
[10]
On the other hand, when lithium metal is used as the negative electrode active material, as charging and discharging are repeated, dendrite is formed on the surface of the negative electrode, thereby increasing the electrode thickness and reducing the cycle characteristics.
Detailed description of the invention
Technical challenge
[11]
The present invention provides a lithium metal battery including a composite solid electrolyte membrane in order to solve the above problems.
[12]
Other objects and advantages of the present invention will be understood by the following description. On the other hand, it will be readily appreciated that the objects and advantages of the present invention can be realized by means or methods described in the claims, and combinations thereof.
Means of solving the task
[13]
An aspect of the present invention provides a lithium metal battery according to the following embodiments.
[14]
The first embodiment,
[15]
As a lithium metal battery,
[16]
The lithium metal battery includes a composite solid electrolyte membrane interposed between the lithium metal negative electrode and the positive electrode,
[17]
The composite solid electrolyte membrane includes a phase change layer containing a plasticizer and a lithium salt;
[18]
A porous polymer sheet layer; And
[19]
It includes a solid polymer electrolyte layer,
[20]
The phase change layer, the porous polymer sheet layer, and the solid polymer electrolyte layer are sequentially stacked,
[21]
The phase change layer is disposed to face the lithium metal negative electrode, relates to a lithium metal battery.
[22]
In the second embodiment, in the first embodiment,
[23]
The plasticizer and the lithium salt are solid at 15 to 25 ℃, relates to a lithium metal battery.
[24]
In the third embodiment, in the first or second embodiment,
[25]
The plasticizer and the lithium salt are liquefied at 30° C. or higher, and relates to a lithium metal battery.
[26]
In the fourth embodiment, in any one of the first to third embodiments,
[27]
The plasticizer has a melting point of 30 to 130 °C,
[28]
The lithium metal battery relates to a lithium metal battery that is activated in a range of more than the melting point of the plasticizer and less than 130 °C.
[29]
In the fifth embodiment, in any one of the first to fourth embodiments,
[30]
The plasticizer includes any one of ethylene carbonate, polyethylene glycol having a weight average molecular weight of 1,000 or more, succinonitrile, or cyclic phosphate, or a mixture of two or more of them. It relates to a lithium metal battery.
[31]
In the sixth embodiment, in any one of the first to fifth embodiments,
[32]
The lithium salt is Li cation + to contain the anion is F - , Cl - , Br - , I - , NO 3 - , N (CN) 2 - , BF 4 - , ClO 4 - , AlO 4 - , AlCl 4 - , PF 6 - , SbF6 - , AsF 6 - , F 2 C 2 O 4 - , BC 4O 8 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 ) 5 PF - , (CF 3 ) 6 P - , CF 3 SO 3 - , C 4 F 9 SO 3 -, CF 3 CF 2 SO 3 - , (CF 3 SO 2 ) 2 N - , (F 2 SO 2 ) 2 N - , CF 3 CF 2 (CF 3 ) 2 CO - , (CF 3 SO 2 ) 2 CH - , CF 3 (CF 2 ) 7SO 3 - , CF 3 CO 2 - , CH 3 CO 2 - , SCN - , (CF 3 CF 2 SO 2 ) 2 N - or relate to that of a lithium metal battery of any two or more of the foregoing.
[33]
In the seventh embodiment, in any one of the first to sixth embodiments,
[34]
The weight ratio of the plasticizer and the lithium salt is 99:1 to 40:60, which relates to a lithium metal battery.
[35]
In the eighth embodiment, in any one of the first to seventh embodiments,
[36]
The thickness of the porous polymer sheet layer is 5 to 50 μm, and the porosity of the porous polymer sheet layer is 40 to 60%, to a lithium metal battery.
[37]
In the ninth embodiment, in any one of the first to eighth embodiments,
[38]
The solid polymer electrolyte layer relates to a lithium metal battery comprising a solid polymer electrolyte.
[39]
In the tenth embodiment, in any one of the first to ninth embodiments,
[40]
The thickness of the solid polymer electrolyte layer is 5 to 300 μm, and the porosity of the solid polymer electrolyte layer is 0 to 30%, to a lithium metal battery.
[41]
In the eleventh embodiment, in any one of the first to tenth embodiments,
[42]
The phase change layer is liquefied at a temperature of 30° C. or higher, and the plasticizer and lithium salt in the liquefied phase change layer are located between the lithium metal negative electrode and the porous polymer sheet layer, and the lithium metal negative electrode and the porous polymer sheet layer It relates to a lithium metal battery to reduce the interfacial resistance between.
[43]
In the twelfth embodiment, in any one of the first to eleventh embodiments,
[44]
The phase change layer is liquefied at a temperature of 30° C. or higher to be impregnated in the porous polymer sheet layer, and to reduce the interface resistance between the porous polymer sheet layer and the solid polymer electrolyte layer, to a lithium metal battery.
[45]
In the thirteenth embodiment, in any one of the first to twelfth embodiments,
[46]
It relates to a lithium metal battery comprising a softened solid polymer electrolyte layer between the solid polymer electrolyte layer and the porous polymer sheet layer.
Effects of the Invention
[47]
The lithium metal battery according to the present invention includes a composite solid electrolyte membrane, and the composite solid electrolyte membrane includes a phase change layer facing the lithium metal negative electrode. The phase change layer is liquefied by heating such as an increase in the internal temperature of the battery, so that the interface resistance between the lithium metal negative electrode and the composite solid electrolyte membrane may be lowered.
[48]
In addition, since the phase change layer is liquefied and exists on the electrode surface, nonuniformity in contact between the composite solid electrolyte membrane and the electrode surface may be reduced. Accordingly, it is possible to increase adhesion between the electrode and the porous polymer sheet layer, and to lower the interface resistance between the porous polymer sheet layer and the solid polymer electrolyte layer.
[49]
The phase change layer may be liquefied to fill a dead space in the electrode. Accordingly, localized lithium dendrite growth can be prevented by uniformly flowing current on the surface of the lithium metal anode. Accordingly, it is possible to increase the ionic conductivity and lower the resistance of lithium ions, improve the life performance of the battery, and significantly increase the capacity retention rate.
[50]
Since the phase change layer is liquefied and functions as a liquid electrolyte, it is possible to improve the output of the battery by increasing the ionic conductivity of the battery.
[51]
Since the lithium metal battery according to the present invention includes a porous polymer sheet layer, it is possible to prevent softening of the solid polymer electrolyte layer generated by direct contact of the liquefied liquid electrolyte with the solid polymer electrolyte layer and the resulting deterioration of mechanical properties. . In addition, it is possible to reduce the growth of lithium dendrites by including the porous polymer sheet layer.
[52]
The present invention can provide a lithium metal battery with improved safety.
Brief description of the drawing
[53]
1 is a perspective view schematically showing a lithium metal battery according to an embodiment of the present invention.
[54]
2 schematically illustrates a lithium metal battery according to a comparative example of the present invention.
[55]
3 is a graph showing a capacity retention rate of a lithium metal battery according to an embodiment and a comparative example of the present invention.
Mode for carrying out the invention
[56]
Hereinafter, the present invention will be described in detail. The terms or words used in the specification and claims should not be construed as being limited to their usual or dictionary meanings, and the inventor may appropriately define the concept of terms in order to describe his own invention in the best way. It should be interpreted as a meaning and concept consistent with the technical idea of ​​the present invention based on the principle that there is. Accordingly, the embodiments described in the present specification and the configurations shown in the drawings are only the most preferred embodiments of the present invention, and do not represent all the technical spirit of the present invention. It should be understood that there may be equivalents and variations.
[57]
[58]
In the entire specification of the present application, when a certain part is said to be ``connected'' with another part, this includes not only ``directly connected'' but also ``electrically connected'' with another element interposed therebetween. .
[59]
[60]
In the entire specification of the present application, when a certain part "includes" a certain constituent element, it means that other constituent elements may be further included rather than excluding other constituent elements unless otherwise stated.
[61]
[62]
The terms "about", "substantially" and the like used throughout the specification of the present application are used as a meaning at or close to the numerical value when manufacturing and material tolerances specific to the stated meaning are presented, and are accurate to aid the understanding of the present application. Or absolute figures are used to prevent unfair use of the stated disclosure by unconscionable infringers.
[63]
[64]
In the entire specification of the present application, the term "combination(s) thereof" included on the surface of the Makushi-type means one or more mixtures or combinations selected from the group consisting of components described in the expression of the Makushi-type, It means to include at least one selected from the group consisting of the above components.
[65]
[66]
In the entire specification of the present application, the description of "A and/or B" means "A or B or both".
[67]
[68]
In addition, when used in this specification, ``comprise'' and/or ``comprising'' refers to the mentioned shapes, numbers, steps, actions, members, elements, and/or the presence of these groups. And does not exclude the presence or addition of one or more other shapes, numbers, actions, members, elements, and/or groups.
[69]
[70]
In the electrode assembly, the solid electrolyte membrane serves as a separator that electrically insulates the positive electrode and the negative electrode in the battery and as a safety device to prevent overheating of the battery. In addition, since the solid electrolyte membrane allows lithium ions to move to the ion conductive layer, charging and discharging of the battery is possible.
[71]
However, since the electrolyte membrane is solid, a separation occurs between the electrode, more specifically, the cathode and the electrolyte membrane, and thus, there is a problem that voids without ion conductivity, that is, a dead space, occur. In addition, in this case, current is concentrated in a part other than the dead space, and the generation of lithium dendrites is accelerated, which causes an internal short circuit.
[72]
In order to solve this problem, the present invention introduces a phase change layer between the lithium metal anode and the electrolyte membrane. The plasticizer and lithium salt in the phase change layer are changed to liquid by heating, such as an increase in the temperature inside the battery, so that the interface resistance between the electrode and the solid electrolyte membrane may be reduced. In addition, ionic conductivity can be increased by reducing dead space, and localized lithium dendrite growth is reduced by uniformly flowing current on the surface of the lithium metal anode, and interfacial adhesion between the electrode and the electrolyte membrane is improved by eliminating voids without ion conductivity. You can increase it.
[73]
Specifically, when the phase change layer is heated by an increase in the internal temperature of the battery, the solid plasticizer in the phase change layer changes into a liquid phase. Thereafter, the liquefied plasticizer acts as a solvent to dissolve the lithium salt. As a result, the solid electrolyte and the solid lithium salt in the phase change layer function as a liquid electrolyte in which the lithium salt is dissolved in a liquefied plasticizer. The resulting liquid electrolyte may be impregnated in the porous polymer sheet layer, may be impregnated in a dead space existing in the electrode, or may exist between the electrode and the porous polymer sheet layer.
[74]
That is, the present invention relates to a lithium metal battery, and to a lithium metal battery including a composite solid electrolyte membrane.
[75]
[76]
The composite solid electrolyte membrane of the present invention is provided with a phase change layer in which the phase changes from a solid phase to a liquid phase as the temperature increases on one side of the outermost surface thereof.
[77]
[78]
According to an embodiment of the present invention, the lithium metal battery,
[79]
It includes a composite solid electrolyte membrane interposed between the lithium metal negative electrode and the positive electrode,
[80]
The composite solid electrolyte membrane includes a phase change layer containing a plasticizer and a lithium salt;
[81]
A porous polymer sheet layer; And
[82]
It includes a solid polymer electrolyte layer,
[83]
The phase change layer, the porous polymer sheet layer, and the solid polymer electrolyte layer are sequentially stacked,
[84]
The phase change layer is disposed to face the lithium metal negative electrode.
[85]
[86]
The phase change layer includes a plasticizer and a lithium salt.
[87]
In a specific embodiment of the present invention, the phase change layer may have a layered structure.
[88]
For example, it may include a first conversion layer containing a plasticizer and a second conversion layer containing a lithium salt. Each of the first conversion layer or the second conversion layer may face the cathode.
[89]
At this time, the plasticizer has a melting point of 30 to 130 °C,
[90]
The lithium metal battery may be activated in a range above the melting point of the plasticizer and below 130 °C.
[91]
In general, a battery is manufactured and then completed into a commercial battery only after undergoing a high-temperature activation step.
[92]
At this time, the high-temperature activation step must be a high temperature equal to or higher than the melting point of the plasticizer, and a temperature higher than room temperature of 30° C. or higher, preferably 35° C. or higher, most preferably 50° C. or higher, and 130° C. or lower, preferably 100° C. Hereinafter, most preferably, the battery may be left without charging and discharging for a predetermined time at a temperature of 90° C. or less, or may be left while charging and discharging.
[93]
The predetermined time may be 10 seconds to 48 hours, preferably 1 minute to 24 hours, and most preferably 1 hour to 8 hours.
[94]
On the other hand, when the temperature of activation exceeds 130° C., curing of the binder may occur, and the porous polymer sheet layer may be thermally contracted. Therefore, it is preferable when the temperature of activation is 130° C. or less, and therefore, it is preferable when the melting point of the plasticizer is also 130° C. or less.
[95]
[96]
2 is a view schematically showing a lithium metal battery to which a conventional solid electrolyte is applied, and FIG. 1 is a view schematically showing a lithium metal battery to which a solid electrolyte according to an embodiment of the present disclosure is applied.
[97]
Referring to FIGS. 1 and 2, in the case of a battery to which a conventional solid electrolyte is applied, when the lithium dendrites grown from the lithium metal negative electrode 10 penetrate the solid polymer electrolyte layer 40 and contact the positive electrode 60, a short circuit is prevented. Can occur. In addition, when the surface of the lithium metal anode is uneven, the growth of lithium dendrites occurs more significantly due to the dead space, which is a pore without ion conductivity that is finely generated between the lithium metal anode 10 and the solid polymer electrolyte layer 40. The resistance between the electrode and the solid polymer electrolyte layer increased and the battery life could have a fatal adverse effect.
[98]
However, according to the present invention, since the porous polymer sheet layer 30 is present, mechanical properties are maintained and softening of the solid polymer electrolyte layer 40 can be reduced.
[99]
In addition, the solid polymer electrolyte layer 50 softened due to the liquefaction of the phase change layer 20 may increase the adhesion between the porous polymer sheet layer 30 and the solid polymer electrolyte layer 40.
[100]
The plasticizer and lithium salt in the phase change layer are solid at 15 to 25°C, or 17 to 25°C, or 19 to 25°C.
[101]
Room temperature in the present invention means 24 to 26 ℃.
[102]
The plasticizer and the lithium salt may be liquefied at 30° C. or higher, or 32° C. or higher, or 35° C. or higher.
[103]
In a specific embodiment of the present invention, the liquefied state may mean a state in which the plasticizer in the solid state has fluidity.
[104]
The liquefied plasticizer and the lithium salt are positioned between the lithium metal negative electrode and the porous polymer sheet layer to reduce the interface resistance between the lithium metal negative electrode and the porous polymer sheet layer.
[105]
In addition, the plasticizer and the lithium salt in the phase change layer are liquefied and function as a liquid electrolyte as the temperature inside the battery increases.
[106]
When the plasticizer and lithium salt in the phase change layer are liquefied to become a liquid electrolyte state, the liquid electrolyte is positioned between the lithium metal negative electrode and the porous polymer sheet layer, and may be impregnated in the porous polymer sheet layer. The liquid electrolyte impregnated in the porous polymer sheet layer may lower the interface resistance between the porous polymer sheet layer and the solid polymer electrolyte layer.
[107]
In addition, the liquefied plasticizer and lithium salt may fill a dead space in the lithium metal negative electrode. Accordingly, the ion conductivity is increased, so that the resistance of the battery can be lowered and the lifespan performance can be improved.
[108]
In the present invention, the plasticizer is in a solid state at 15 to 25° C. and can be used without limitation as long as it can be liquefied as the temperature rises.
[109]
In a specific embodiment of the present invention, the plasticizer is solid in the above temperature range, but the internal temperature rises during the aging step of the battery or driving the battery to change to a liquid state. For example, if the aging condition is performed at about 60° C. for about 10 seconds after assembling the battery, the plasticizer may be liquefied. At this time, the plasticizer changed to a liquid phase acts as a solvent to dissolve the solid lithium salt, so that both the plasticizer and the lithium salt can be maintained in a liquid state. In addition, the plasticizer and the lithium salt once turned into a liquid remain in a liquid state even when the temperature is lowered to 15 to 25 °C again. This appears to be due to the lower melting point of the plasticizer and the lithium salt in a mixture state.
[110]
As the plasticizer and the lithium salt in the phase change layer are present in a liquid state, current flows uniformly on the surface of the lithium metal negative electrode, thereby preventing local growth of lithium dendrites.
[111]
In a specific embodiment of the present invention, when the plasticizer changes to a liquid state, the battery driving temperature need not necessarily be higher than the melting point of the plasticizer.
[112]
In a specific embodiment of the present invention, the plasticizer is any one of ethylene carbonate, polyethylene glycol having a weight average molecular weight of 1,000 or more, succinonitrile, or cyclic phosphate. Or a mixture of two or more of these may be mentioned.
[113]
In a specific embodiment of the present invention, the plasticizer is present as a solid at 15 to 25°C, but any material that is liquefied at 30°C or higher can be used.
[114]
For example, ethylene carbonate (EC) with a melting point of about 37°C, polyethylene glycol (PEG) with a melting point of about 35°C and a weight average molecular weight of 1,000 or more, and succinonitrile with a melting point of about 57°C. (Succcinonitrile, SN) or a cyclic phosphate (CP) having a melting point of about 65 °C, or a mixture of two or more of them.
[115]
On the other hand, propylene carbonate (PC) with a melting point of about -49 ℃, polyethylene glycol (PEG) with a weight average molecular weight of less than 1000, or less than 800, or less than 600, and polyethylene with a melting point of about -23 ℃ Since glycol dimethyl ether (PEGDME) and diethyl phthalate (DEP) having a melting point of about -4 °C exist in a liquid state at room temperature, it is difficult to apply the plasticizer of the present invention.
[116]
In a specific embodiment of the present invention, the plasticizer may be ethylene carbonate. The ethylene carbonate has a melting point of about 37° C. and exists in a solid state at room temperature. When heat is applied to the solid ethylene carbonate, it is liquefied at about 60° C., and the liquefied ethylene carbonate can dissolve the surrounding solid lithium salt. Thereafter, the ethylene carbonate once liquefied remains as a liquid at room temperature even when the temperature decreases again. This seems to be because the solute lithium salt is dissolved in ethylene carbonate, a solvent, which lowers the melting point of the mixture. A liquid electrolyte containing such a plasticizer and a lithium salt fills the death space of the electrode to increase the ionic conductivity of the battery. In addition, it is possible to lower the resistance of the battery and improve the life performance.
[117]
In a specific embodiment of the present invention, the ethylene carbonate is generally used in a non-aqueous electrolyte. Therefore, when the ethylene carbonate is liquefied, it can function as a liquid electrolyte applicable to most batteries, and there is an advantage in that there are no impurities. In the present invention, the lithium salt is in a state of 15 to 25 °C at room temperature, and can be used without limitation as long as it is ionizable in the electrolyte. The lithium salt can be represented by Li + X - .
[118]
In a specific exemplary embodiment of the present invention, the lithium salt is Li cation + to contain the anion is F - , Cl - , Br - , I - , NO 3 - , N (CN) 2 - , BF 4 - , ClO 4 - , AlO 4 - , AlCl 4 - , PF 6 - , SbF6 - , AsF 6 - , F 2 C 2 O 4 - , BC 4 O 8 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 ) 5 PF - , (CF 3 ) 6 P - , CF 3 SO 3 - , C 4 F 9 SO 3 - , CF 3 CF 2 SO 3 - , (CF 3 SO 2 ) 2 N - , (F 2 SO 2 ) 2 N - , CF 3 CF 2 (CF 3 ) 2 CO - , (CF 3 SO 2 ) 2 CH - , CF 3 (CF 2 ) 7 SO 3 - , CF 3 CO 2 - , CH 3 CO 2 - , SCN - , and (CF 3 CF 2 SO 2 ) 2 N - can include at least one selected from the group consisting of.
[119]
[120]
In a specific embodiment of the present invention, when the plasticizer and the lithium salt are liquefied, the concentration of the lithium salt is 0.05 to 5.0 moles, or 0.2 to 4.5 moles, or 0.2 to 3.0 moles based on the total mixture of the plasticizer and lithium salt. , Or 1.0 to 2.0 moles. The upper limit of the lithium salt concentration may be 5.0 mol or less, 4.5 mol or less, or 3.0 mol or less, or 2.0 mol or less, and the lower limit of the lithium salt concentration may be 0.05 mol or more, 0.2 mol or more, 1.0 mol or more.
[121]
When the concentration of the lithium salt satisfies the above numerical range, the liquefied plasticizer may not be solidified again even if the temperature decreases later. In addition, when the concentration of the lithium salt satisfies the above numerical range, the viscosity of the lithium salt in the liquefied mixture is appropriately maintained, thereby lowering the low-temperature output, which may be advantageous in terms of economy. In addition, when the plasticizer and the lithium salt in the phase change layer are later liquefied within the numerical range, they have ionic conductivity suitable for use as a liquid electrolyte, and may have a concentration suitable for reducing the interface resistance with the electrode.
[122]
[123]
In a specific embodiment of the present invention, the plasticizer and the lithium salt may be included in a weight ratio of 99:1 to 40:60, or 99:1 to 45:55, or 98:2 to 48:52.
[124]
In a specific embodiment of the present invention, for example, based on the total content of the liquefied phase change layer, when the molar concentration of the lithium salt is 0.1 mol (M), the weight ratio of the plasticizer and the lithium salt may be 98:2. .
[125]
In a specific embodiment of the present invention, based on the total content of the liquefied phase change layer, when the molar concentration of the lithium salt is 2.0 mol, the weight ratio of the plasticizer and the lithium salt may be 70:30.
[126]
In a specific embodiment of the present invention, for example, based on the total content of the liquefied phase change layer, when the molar concentration of the lithium salt is 5.0 mol (M), the weight ratio of the plasticizer and the lithium salt may be 48:52. .
[127]
When the weight ratio of the plasticizer and the lithium salt satisfies the above numerical range, the plasticizer and the lithium salt in the phase change layer have ionic conductivity suitable for use as a liquid electrolyte when they are later liquefied, and a weight ratio suitable for reducing the interface resistance with the electrode Can have
[128]
[129]
In the present invention, the lithium metal battery includes a porous polymer sheet layer in a composite solid electrolyte membrane.
[130]
The porous polymer sheet layer may reduce direct contact with the liquefied plasticizer and lithium salt and the solid polymer electrolyte layer. That is, the porous polymer sheet layer functions as a barrier capable of minimizing softening of the solid polymer electrolyte layer. More specifically, in the phase change layer in the present invention, the plasticizer and the lithium salt in the phase change layer are liquefied by heat or the like. When the liquefied plasticizer contacts the solid polymer electrolyte layer, the surface of the solid polymer electrolyte layer is softened. In the present invention, such softening can be prevented or minimized by including a porous polymer sheet layer.
[131]
In addition, it is possible to reduce the growth of lithium dendrites by including the porous polymer sheet layer.
[132]
In addition, in the present invention, the porous polymer sheet layer is inserted between the negative electrode and the solid polymer electrolyte layer to further contribute to the safety of the battery. In particular, it is possible to increase the mechanical strength of the battery. This seems to be because the porous polymer sheet layer itself serves as a supporting layer and at the same time, the porous polymer sheet layer is impregnated with a liquefied plasticizer and a lithium salt to fill the pores in the porous polymer sheet layer.
[133]
As the mechanical strength as described above increases, the present invention can provide a lithium metal battery that is more improved against physical impacts such as nail penetration, compression, and impact.
[134]
The porous polymer sheet layer may be any planar porous polymer substrate used in an electrochemical device.
[135]
In a specific embodiment of the present invention, the porous polymer sheet layer is polyethylene; Polypropylene; Polybutylene; Polypentene; Polyhexene; Polyoxene; Or a copolymer of two or more of ethylene, propylene, butene, pentene, 4-methylpentene, hexene, and octene; Any one or a mixture of two or more of them may be included. However, it is not limited thereto.
[136]
The thickness of the porous polymer sheet layer may be 5 µm to 50 µm, or 7.5 µm to 30 µm, or 10 µm to 20 µm. In the above range, the lower limit of the thickness may be 5 μm or more, or 7.5 μm or more, or 10 μm or more, and the thickness may be 50 μm or less, or 30 μm or less, or 20 μm or less. When the thickness of the porous polymer sheet layer satisfies the above numerical range, the liquefied plasticizer can be sufficiently impregnated, and at the same time, the distance through which lithium ions travel is short, so that excellent ionic conductivity can be obtained.
[137]
The porosity of the porous polymer sheet layer may be 30 to 60%, or 35 to 55%, or 40 to 50%. The lower limit of the porosity may be 30%, or 35%, or 40%, the upper limit of the porosity may be 60%, or 55%, or 50%, and may be a combination of each of the lower and lower limits. . The liquefied plasticizer and lithium salt within the numerical range prevent the solid electrolyte from being liquefied by passing through the pores in the porous polymer sheet layer, and at the same time, the liquefied lithium salt passes through the pores in the porous polymer sheet layer. It can be satisfied at the same time to increase the conductivity. In the present invention, in the case of the porous polymer sheet layer, since the plasticizer and the lithium salt exist in a liquefied state, porosity is important compared to the pore size.
[138]
In the present invention, the porosity can be measured by the following method.
[139]
The porosity measurement method was to measure the diameter of the pores filled with mercury at a constant pressure according to ASTM D 4284-92, and the applied pressure range was between 0.5 and 60,000 psi while continuously applying pressure to The porosity was measured by measuring the pores in and measuring the volume of mercury filling the separator at this time. The measurement is automatically measured and the calculated value is output. The equipment used is Autopore IV 9500 from Micrometrics, and the size range of pores that can be measured is 0.003 ㎛ to 360 ㎛.
[140]
In a specific embodiment of the present invention, the porous polymer sheet layer is polyethylene; Polypropylene; Polybutylene; Polypentene; Polyhexene; Polyoxene; Or a copolymer of two or more of ethylene, propylene, butene, pentene, 4-methylpentene, hexene, and octene; Any one or a mixture of two or more of them may be included. However, it is not limited thereto.
[141]
[142]
In the present invention, the solid polymer electrolyte layer is an ion conductive layer through which lithium ions pass, and an insulating layer through which electrons do not pass.
[143]
The solid polymer electrolyte layer is partially softened by directly contacting the liquid electrolyte passing through the porous polymer sheet layer. The softened solid electrolyte may increase adhesion between the lithium metal negative electrode and the composite solid electrolyte membrane.
[144]
In a specific embodiment of the present invention, the solid polymer electrolyte layer may include a solid polymer electrolyte.
[145]
In a specific embodiment of the present invention, the solid polymer electrolyte may be a solid polymer electrolyte having excellent reducibility. Since the solid polymer electrolyte of the present invention serves to transport lithium ions in the electrode, a material having high ionic conductivity, for example, 10 -6 S/cm or more, 10 -5 S/cm or more, or 10 -4 Anything that is S/cm or more can be used, and is not limited to a specific component.
[146]
In a specific embodiment of the present invention, the solid polymer electrolyte layer may include a solid polymer electrolyte and a lithium salt.
[147]
For example, the solid polymer electrolyte layer may be one in which ions of a dissociated salt can be moved within the polymer by adding a lithium salt to a polymer containing a hetero element such as oxygen, nitrogen, and sulfur.
[148]
In a specific embodiment of the present invention, the solid polymer electrolyte is a polyether polymer, a polycarbonate polymer, an acrylate polymer, a polysiloxane polymer, a phosphazene polymer, a polyethylene derivative, an alkylene oxide derivative, a phosphate ester polymer. , Poly-editation lysine (agitation lysine), polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, a polymer containing an ionic dissociation group, and the like. In a specific embodiment of the present invention, the solid polymer electrolyte is a polymer resin, such as polyethylene oxide, polyethylene glycol, polypropylene oxide, polyphosphazene, and polysiloxane. ) And any one selected from the group consisting of copolymers thereof, or a mixture of two or more of them. However, the present invention is not particularly limited thereto, and a solid polymer electrolyte commonly used as a solid electrolyte may be used without limitation.
[149]
In addition, in a specific embodiment of the present invention, the solid polymer electrolyte is a polymer resin and is copolymerized with an amorphous polymer comonomer such as PMMA, polycarbonate, polysiloxane (PDMS) and/or phosphazene on the PEO (polyethylene oxide) main chain. The branched copolymer, comb-like polymer, and crosslinked polymer resin may be included, and may be a mixture of the above polymers.
[150]
In a specific exemplary embodiment of the present invention, the lithium salt is Li cation + to contain the anion is F - , Cl - , Br - , I - , NO 3 - , N (CN) 2 - , BF 4 - , ClO 4 - , AlO 4 - , AlCl 4 - , PF 6 - , SbF6 - , AsF 6 - , F 2 C 2 O 4 - , BC 4 O 8 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 ) 5 PF - , (CF 3 ) 6 P - , CF 3 SO 3 - , C 4 F 9 SO 3 - , CF 3 CF 2 SO 3 - , (CF 3 SO 2 ) 2 N - , (F 2 SO 2 ) 2 N - , CF 3 CF 2 (CF 3 ) 2 CO - , (CF 3 SO 2 ) 2 CH - , CF 3 (CF 2 ) 7 SO 3 - , CF 3 CO 2 - , CH 3 CO 2 - , SCN - , and (CF 3 CF 2 SO 2 ) 2 N - can include at least one selected from the group consisting of.
[151]
In a specific embodiment of the present invention, the thickness of the solid polymer electrolyte layer may be 5 μm to 300 μm, or 10 μm to 200 μm, or 25 μm to 100 μm. The thickness of the solid polymer electrolyte layer may be 300 μm or less, 200 μm or less, or 100 μm or less, and the solid polymer electrolyte layer thickness may be 5 μm or more, or 10 μm or more, or 25 μm or more. Within the above numerical range, cell performance may be excellent and at the same time, assembly processability may be excellent.
[152]
In a specific embodiment of the present invention, the porosity of the solid polymer electrolyte layer may be 0 to 30% or 3 to 10%, or 5 to 7%. The porosity of the solid polymer electrolyte layer may be 30% or less, or 10% or less, or 7% or less, and the porosity of the solid polymer electrolyte layer may be 0% or more, or 3% or more, or 5% or more.
[153]
In the case of the solid polymer electrolyte layer, since lithium ions are transferred through the solid polymer electrolyte, the higher the porosity, the higher the resistance. In the case of the present invention, the solid polymer electrolyte layer may have excellent ionic conductivity by satisfying the numerical range of the porosity.
[154]
The pore diameter of the solid polymer electrolyte layer may be generally 0.001 to 10 μm. In a specific embodiment of the present invention, the lower limit of the pore diameter may be 0.01 μm or more and 0.1 μm or more, and the upper limit of the pore diameter may be 7 μm or less and 5 μm or less.
[155]
In the present invention, when the plasticizer of the present invention is phase-changed to a liquid state, the solid polymer electrolyte may be included as long as it has a property of being softened by contacting the phase-changed plasticizer.
[156]
[157]
In the present invention, softening may mean that the strength of the solid polymer electrolyte layer is lowered. In the present invention, softening may mean that the viscosity of the solid polymer electrolyte is lowered. In the present invention, softening may mean that at least one of the strength, viscosity, and elastic modulus of the solid polymer electrolyte layer is lowered.
[158]
Since the solid polymer electrolyte is chemically stable, it is safe even in the charging and discharging process. In addition, the solid polymer electrolyte is easy to handle and is advantageous in an electrode assembly assembly process.
[159]
[160]
The lithium metal battery according to an aspect of the present invention may form a phase change layer by spraying a plasticizer powder and a lithium salt powder on the surface of the lithium metal applied on the current collector. Thereafter, a porous polymer sheet layer is laminated on the surface of the phase change layer. Next, a lithium metal battery may be manufactured by laminating a solid polymer electrolyte layer on the porous polymer sheet layer.
[161]
[162]
In addition, in a specific embodiment of the present invention, a lithium metal battery can be manufactured by the following method.
[163]
First, after preparing a solid polymer electrolyte layer, a porous polymer sheet layer is laminated on one surface of the solid polymer electrolyte layer. Thereafter, a phase change layer may be formed by spraying a plasticizer powder and a lithium salt powder on the porous polymer sheet layer to prepare a composite solid electrolyte membrane.
[164]
Thereafter, a lithium metal battery may be manufactured by laminating the composite solid electrolyte membrane on the surface of the lithium metal coated or deposited on the current collector.
[165]
[166]
However, a method of manufacturing a lithium metal battery according to an aspect of the present invention is not limited to the above methods, and is not particularly limited as long as it is capable of manufacturing a lithium metal battery according to the present invention.
[167]
[168]
The negative electrode for a lithium metal battery includes a negative active material layer positioned on a current collector. The negative active material layer may include at least one element belonging to an alkali metal, an alkaline earth metal, a group 3B, and a transition metal as a negative active material. Non-limiting examples of the alkali metal may include at least one metal selected from the group consisting of lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs), and francium (Fr). . Non-limiting examples of the alkaline earth metal include at least one metal selected from the group consisting of beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), barium (Ba), and radium (Ra). . Non-limiting examples of the 3B group may include at least one metal selected from the group consisting of aluminum (Al), gallium (Ga), indium (In), and thallium (Tl). Non-limiting examples of the transition metal include at least one metal selected from the group consisting of nickel (Ni), copper (Cu), zinc (Zn), cobalt (Co), manganese (Mn), and chromium (Cr). have.
[169]
In a specific embodiment of the present invention, the negative active material layer may include at least one of a metal thin film, a metal alloy, and powders thereof.
[170]
In a specific embodiment of the present invention, the negative electrode active material includes lithium metal, and additionally, any one selected from the group consisting of a lithium alloy, a lithium metal composite oxide, a lithium-containing titanium composite oxide (LTO), and a combination thereof Two or more of them may be included. In this case, the lithium alloy includes an element capable of alloying with lithium, and the elements capable of alloying with lithium include Si, Sn, C, Pt, Ir, Ni, Cu, Ti, Na, K, Rb, Cs , Fr, Be, Mg, Ca, Sr, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, or alloys thereof.
[171]
The thickness of the negative active material layer may be 5 to 40 μm. In a specific embodiment of the present invention, the lower limit of the thickness of the negative active material layer may be 5 µm, 7 µm, or 10 µm or more, and the upper limit of the thickness of the negative active material layer may be 40 µm, 30 µm, or 20 µm or less. Each can be a combination. Within the above numerical range, lithium ions may be sufficiently diffused into the negative active material layer.
[172]
In a specific embodiment of the present invention, the negative active material layer may be prepared by coating, bonding, rolling, or depositing a metal foil on a flat current collector. Alternatively, it may be prepared by applying metal powder on the current collector. Meanwhile, the negative active material layer may be formed of only a metal thin film or a metal alloy without a current collector. In a specific embodiment of the present invention, the negative active material layer may be prepared by physically bonding or rolling a lithium metal to a current collector. In a specific embodiment of the present invention, the negative active material layer may be prepared by electro-depositing lithium metal or chemical vapor deposition on a current collector.
[173]
That is, in the present invention, the lithium metal negative electrode may not require a binder polymer when manufacturing the negative electrode active material layer.
[174]
The present invention has the advantage of obtaining a high energy density by using a lithium metal or a lithium alloy as a negative electrode as a negative electrode active material.
[175]
[176]
The positive electrode to be applied together with the composite solid electrolyte membrane of the present invention is not particularly limited, and an electrode active material layer may be prepared in a form bound to an electrode current collector according to a conventional method known in the art.
[177]
In a specific embodiment of the present invention, the positive electrode may include a current collector and a positive electrode active material layer formed on the surface of the current collector, and the positive electrode active material layer may further include a positive electrode active material, a solid electrolyte, a binder, and a conductive material. have.
[178]
The positive electrode current collector is generally made to have a thickness of 3 to 500 μm. Such a positive electrode current collector is not particularly limited as long as it has high conductivity without causing chemical changes in the battery, for example, stainless steel, aluminum, nickel, titanium, calcined carbon, or the surface of aluminum or stainless steel. For example, those treated with carbon, nickel, titanium, silver or the like may be used. In addition, the positive electrode current collector may increase the adhesion of the positive electrode active material by forming fine irregularities on its surface, and various forms such as films, sheets, foils, nets, porous bodies, foams, and nonwoven fabrics are possible.
[179]
The positive electrode active material is not particularly limited as long as it is a positive electrode active material that can be used for a positive electrode of an electrochemical device. For example, the positive electrode active material is LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , LiCoPO 4 , LiFePO 4 , LiNiMnCoO 2 and LiNi 1 -xy- z Co x M1 y M2 z O 2 (M1 and M2 are independently of each other Al, Ni, Co, Fe, Mn, V, Cr, Ti, W, Ta, Mg, and any one selected from the group consisting of Mo, and x, y and z are independently of each other as an atomic fraction of the oxide composition elements, 0 = x <0.5, 0 ≤= y <0.5, 0 ≤ z <0.5, x+y+z = 1), or a mixture of two or more of them.
[180]
The solid electrolyte included in the positive electrode may be a polymer electrolyte or an inorganic solid electrolyte.
[181]
In a specific embodiment of the present invention, the polymer solid electrolyte is, for example, a polyether polymer, a polycarbonate polymer, an acrylate polymer, a polysiloxane polymer, a phosphazene polymer, a polyethylene derivative, an alkylene oxide derivative. , Phosphoric acid ester polymer, poly agitation lysine, polyester sulfide, polyvinyl alcohol, polyvinylidene fluoride, a polymer including an ionic dissociation group, and the like.
[182]
In a specific embodiment of the present invention, the inorganic solid electrolyte may be an oxide-based or sulfide-based solid electrolyte.
[183]
[184]
In a specific embodiment of the present invention, the sulfide-based solid electrolyte includes Li, X and S, wherein X is a group containing P, Ge, B, Si, Sn, As, Cl, F, and I It may include one or more selected from.
[185]
In a specific embodiment of the present invention, the oxide-based solid electrolyte includes Li, A and O, and A includes at least one selected from the group including La, Zr, Ti, Al P, and I can do.
[186]
In a specific embodiment of the present invention, a lithium salt may be further included in the positive electrode active material layer.
[187]
In a specific exemplary embodiment of the present invention, the lithium salt is Li cation + to contain the anion is F - , Cl - , Br - , I - , NO 3 - , N (CN) 2 - , BF 4 - , ClO 4 - , AlO 4 - , AlCl 4 - , PF 6 - , SbF6 - , AsF 6 - , F 2 C 2 O 4 - , BC 4 O 8 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 ) 5 PF - , (CF 3 ) 6 P - , CF 3 SO 3 - , C 4 F 9 SO 3 - , CF 3 CF 2 SO 3 - , (CF 3 SO 2 ) 2 N - , (F 2 SO 2 ) 2 N - , CF 3 CF 2 (CF 3 ) 2 CO - , (CF 3 SO 2 ) 2 CH - , CF 3 (CF 2 ) 7 SO 3 - , CF 3 CO 2 - , CH 3 CO 2 - , SCN - , and (CF 3 CF 2 SO 2 ) 2 N - can include at least one selected from the group consisting of.
[188]
[189]
Hereinafter, examples will be described in detail in order to describe the present invention in detail. However, the embodiments according to the present invention may be modified in various other forms, and the scope of the present invention should not be construed as being limited to the embodiments described below. Embodiments of the present invention are provided to more completely describe the present invention to those with average knowledge in the art.
[190]
[191]
Example 1
[192]
1) Preparation of anode
[193]
As a cathode active material NCM811 (LiNi 0 . 8 Co 0 . 1 Mn 0 . 1 O 2 ) 80 parts by weight of a solid electrolyte as the polyethylene oxide (PEO) 11 parts by weight, LITFSI as an electrolyte salt, 3 parts by weight, the conductive material (VGCF) 3 After mixing parts by weight and 3 parts by weight of a binder polymer (PVDF), a solvent AN (Acetonitrile) was further added in consideration of the viscosity to prepare a positive electrode active material slurry.
[194]
The prepared positive electrode active material slurry was applied to an aluminum current collector having a thickness of 20 μm, and then vacuum-dried at 120° C. for 24 hours to prepare a positive electrode.
[195]
[196]
2) Preparation of the cathode
[197]
A lithium metal negative electrode (Honjo Co.) in which a 20 µm-thick lithium metal was bonded to both sides of a 10 µm-thick copper foil was used.
[198]
[199]
3) Manufacture of lithium metal battery
[200]
On the surface of the negative electrode active material layer in the negative electrode prepared in 2) above, a solid ethylene carbonate 40mg/cm 2 plasticizer powder, LITFSI (Lithi㎛ bis (trifluoromethanesulfonyl)imide) lithium salt powder 2.0 mol (M) (the 2M is the lithium A phase change layer was formed by spraying (based on 1 L of an ethylene carbonate solution in which the salt was dissolved).
[201]
Thereafter, a porous polyethylene substrate (SK company) having a thickness of 20 μm, which is a porous polymer sheet layer, was laminated on the phase change layer.
[202]
Next, a 100 μm-thick solid polymer electrolyte layer was prepared in which polyethylene oxide and lithium salt were mixed at a weight ratio of 70:30, respectively, and laminated on the porous polyethylene substrate.
[203]
Thereafter, the positive electrode prepared as follows was laminated on the porous polyethylene substrate to prepare an electrode assembly and then sealed to prepare a coin cell. After that, aging was performed at 60° C. for 1 hour. After the coin cell was manufactured, the plasticizer was present in a liquid state at room temperature.
[204]
[205]
Example 2
[206]
First, a composite solid electrolyte membrane was prepared by the following method.
[207]
A solid polymer electrolyte layer having a thickness of 100 μm was prepared in which polyethylene oxide and lithium salt were mixed at a weight ratio of 70:30, respectively.
[208]
A porous polyethylene substrate (SK company) having a thickness of 20 μm, which is a porous polymer sheet layer, was laminated on the solid polymer electrolyte layer.
[209]
Thereafter, ethylene carbonate 40 mg/cm 2 plasticizer powder, LITFSI lithium salt powder 2.0 mol (M) (the 2M is based on 1 L of ethylene carbonate solution in which the lithium salt is dissolved) on the porous polyethylene substrate Was prepared.
[210]
The prepared composite solid electrolyte membrane was interposed between the lithium metal anode and the cathode according to Example 1 to prepare an electrode assembly. The electrode assembly was charged into a pouch and then sealed to manufacture a coin cell. Thereafter, it was aged at 60° C. for 1 hour. After the coin cell was manufactured, the plasticizer was present in a liquid state at room temperature.
[211]
[212]
Example 3
[213]
A coin cell was prepared in the same manner as in Example 1, except that Succinonitrile was used instead of ethylene carbonate as a plasticizer. After the coin cell was manufactured, the plasticizer was present in a liquid state at room temperature.
[214]
[215]
Comparative Example 1
[216]
A coin cell was prepared in the same manner as in Example 1, except that the phase change layer and the porous polyethylene substrate, which is a porous polymer sheet layer, were not used.
[217]
[218]
Comparative Example 2
[219]
A coin cell was manufactured in the same manner as in Example 1, except that a porous polyethylene substrate, which is a porous polymer sheet layer, was not used.
[220]
In the case of Comparative Example 2, only the phase change layer was present without the porous polymer sheet layer. In this case, the initial life was excellent, but lithium dendrite was generated in the lithium metal negative electrode, and a short circuit occurred in the cell.
[221]
[222]
Comparative Example 3
[223]
A coin cell was manufactured in the same manner as in Example 1, except that propylene carbonate, which is a liquid at room temperature, was used as a plasticizer.
[224]
In the case of Comparative Example 3, it is similar to a general lithium-ion secondary battery and has excellent lifespan characteristics. However, it is inferior in terms of safety.
[225]
[226]
Comparative Example 4
[227]
A coin cell was manufactured in the same manner as in Example 1, except that lithium salt powder was not included when forming the phase change layer.
[228]
In the case of Comparative Example 4, after the coin cell was manufactured, the plasticizer was present in a solid state at room temperature, and the coin cell was not operated, so the characteristics of the coin cell could not be measured.
[229]
[230]
Experimental example
[231]
(1) Capacity retention measurement
[232]
The lithium metal batteries of Examples and Comparative Examples were charged by CC-CV to 4.25V at 0.1C at room temperature, and then discharged at a constant current to 3V at 0.1C to repeat 10 cycles to check capacity retention. The results for this are shown in FIG. 3. As shown in Figure 3, in the case of Comparative Example 1 not provided with the phase change layer and the porous polymer sheet layer, it can be seen that the capacity retention rate decreases rapidly. In addition, in the case of Comparative Example 2 without a porous polymer sheet layer, while the initial life was excellent, lithium dendrite was generated in the lithium metal negative electrode, resulting in a short circuit in the cell.
[233]
[234]
(2) Porosity measurement
[235]
The porosity measurement method was to measure the diameter of the pores filled with mercury at a constant pressure according to ASTM D 4284-92, and the applied pressure range was between 0.5 and 60,000 psi while continuously applying pressure to The porosity was measured by measuring the pores in and measuring the volume of mercury filling the separator at this time. The measurement is automatically measured and the calculated value is output. The equipment used is Autopore IV 9500 from Micrometrics, and the size range of pores that can be measured is 0.003 ㎛ to 360 ㎛.
[236]
[237]
(3) Measurement of pore diameter
[238]
Mean flow pore size (MFPS) and maximum pore size are measured using an automated capillary flow porometer [PMI (Porous Materials Inc.), Model CFP-1200AEL (CFP-34RTF8A-X-6-L4)] I did. The wetting fluid used for the measurement was galwick acid (surface tension 15.9 dynes/cm). The diameter of the adapter plate was 21 mm, and was measured by wet-up/dry-up method.
[239]
[240]
[Explanation of code]
[241]
100, 200: electrode assembly
[242]
10: lithium metal cathode
[243]
20: phase change layer
[244]
30: porous polymer sheet layer
[245]
40: solid polymer electrolyte layer
[246]
50: softened solid polymer electrolyte layer
[247]
60: anode
Claims
[Claim 1]
A lithium metal battery, wherein the lithium metal battery includes a composite solid electrolyte membrane interposed between a lithium metal negative electrode and a positive electrode, and the composite solid electrolyte membrane comprises a phase change layer including a plasticizer and a lithium salt; A porous polymer sheet layer; And a solid polymer electrolyte layer, wherein the phase change layer, the porous polymer sheet layer, and the solid polymer electrolyte layer are sequentially stacked, and the phase change layer is disposed to face a lithium metal negative electrode. battery.
[Claim 2]
The lithium metal battery according to claim 1, wherein the plasticizer and the lithium salt are solid at 15 to 25°C.
[Claim 3]
The lithium metal battery according to claim 1, wherein the plasticizer and the lithium salt are liquefied at 30°C or higher.
[Claim 4]
The lithium metal battery according to claim 1, wherein the plasticizer has a melting point of 30 to 130°C, and the lithium metal battery is activated at a melting point of the plasticizer or more and 130°C or less.
[Claim 5]
The method of claim 1, wherein the plasticizer is one of ethylene carbonate, polyethylene glycol having a weight average molecular weight of 1,000 or more, succinonitrile, or cyclic phosphate, or two of them. One containing a mixture of more than one species, lithium metal battery.
[Claim 6]
The method of claim 1, wherein the lithium salt is Li cation + includes, as the anion is F - , Cl - , Br - , I - , NO 3 - , N (CN) 2 - , BF 4 - , ClO 4 - , AlO 4 - , AlCl 4 - , PF 6 - , SbF6 - , AsF 6 - , F 2 C 2 O 4 - , BC 4O 8 - , (CF 3 ) 2 PF 4 - , (CF 3 ) 3 PF 3 - , (CF 3 ) 4 PF 2 - , (CF 3 ) 5 PF - , (CF 3 ) 6 P - , CF 3 SO 3 - , C 4 F 9 SO 3 -, CF 3 CF 2 SO 3 - , (CF 3 SO 2 ) 2 N - , (F 2 SO 2 ) 2 N - , CF 3 CF 2 (CF 3 ) 2 CO - , (CF 3 SO 2 ) 2 CH - , CF 3 (CF 2 ) 7SO 3 - , CF 3 CO 2 - , CH 3 CO 2 - , SCN - , (CF 3 CF 2 SO 2 ) 2 N - or that the lithium metal battery of any two or more of the foregoing.
[Claim 7]
The lithium metal battery according to claim 1, wherein the weight ratio of the plasticizer and the lithium salt is 99:1 to 40:60.
[Claim 8]
The lithium metal battery according to claim 1, wherein the porous polymer sheet layer has a thickness of 5 to 50 µm and a porosity of the porous polymer sheet layer is 40 to 60%.
[Claim 9]
The lithium metal battery according to claim 1, wherein the solid polymer electrolyte layer contains a solid polymer electrolyte.
[Claim 10]
The lithium metal battery according to claim 1, wherein the solid polymer electrolyte layer has a thickness of 5 to 300 µm, and the solid polymer electrolyte layer has a porosity of 0 to 30%.
[Claim 11]
The method of claim 1, wherein the phase change layer is liquefied at a temperature of 30 °C or higher, and the plasticizer and lithium salt in the liquefied phase change layer are located between the lithium metal negative electrode and the porous polymer sheet layer, and the lithium metal negative electrode To reduce the interface resistance between the porous polymer sheet layer and the lithium metal battery.
[Claim 12]
The lithium metal of claim 1, wherein the phase change layer is liquefied at a temperature of 30° C. or higher to be impregnated in the porous polymer sheet layer, and to reduce the interface resistance between the porous polymer sheet layer and the solid polymer electrolyte layer. battery.
[Claim 13]
The lithium metal battery according to claim 1, comprising a softened solid polymer electrolyte layer between the solid polymer electrolyte layer and the porous polymer sheet layer.