Cathode material, electrochemical device and electronic device

Abstract

To provide a cathode material, an electrochemical device using the cathode material, and an electronic device, the cathode material having a stable crystal structure, and the electrochemical device being capable of holding a relatively high capacity and excellent cycle characteristics at high voltage.SOLUTION: A cathode material includes particles having a P63mc crystal phase structure, and a particle size distribution curve diagram includes a first peak and a second peak. The cathode material includes a first particle and a second particle, and the first particle is a particle represented by the first peak, while the second particle is a particle represented by the second peak. Both the first particle and the second particle have the P63mc crystal phase structure. The average particle diameter of the first particle is 3 μm to 12 μm. The average particle diameter of the second particle is 15 μm to 30 μm. The particle diameter of the particle represented by the first peak is smaller than the particle diameter of the particle represented by the second peak. When the peak area of the first peak is represented by S1 and the peak area of the second peak is represented by S2, S1 and S2 satisfy 0<S1 / S2<1, and there are holes and gaps inside the particles of the cathode material.SELECTED DRAWING: None

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application was filed on December 11, 2020, and is related to the invention entitled "Positive electrode material, electrochemical device Priority based on Chinese Patent Application No. 202011460086.8, "Device and Electronic Apparatus" The entire contents of this Chinese patent application are incorporated herein by reference. [Technical field]

[0002] The present invention relates to the field of electrochemical technology, in particular to positive electrode materials, electrochemical devices and electronic devices. This is related to. [Background technology]

[0003] With the development and advancement of electrochemical devices (e.g., lithium-ion batteries), the demand for their capacity is One of the important ways to improve the capacity of electrochemical devices is through the use of electrochemical The goal is to increase the voltage of electrochemical devices, but the positive electrode material in high-voltage electrochemical devices has a crystalline structure. The capacity is unstable, the capacity fades rapidly, and the cycle characteristics are significantly reduced.

[0004] Currently, the common cores used in electrochemical devices (e.g., lithium-ion batteries) The lithium baltic oxide positive electrode material has an R-3m crystal phase structure and its theoretical capacity is 273.8mA. h / g, and it has good cycle characteristics and safety properties, and holds an important position in the positive electrode material market. To obtain higher specific energy, the lithium cobalt oxide material is opened in the direction of high voltage. Currently, the capacity of lithium cobalt oxide material is 4.5V when the charging voltage is 4.5V. To improve the capacity of the lithium cobalt oxide material, the cobalt Attempts have been made to release more lithium ions from the lithium tungsten oxide crystal structure, but As the voltage increases, lithium ions are released from the crystal structure of the lithium cobalt oxide. When the lithium cobalt oxide material is charged, a series of irreversible phase changes occur, and the cycle characteristics and The storage characteristics are significantly reduced, and the interfacial side reactions increase under high voltage, causing the dissolution of cobalt metal. This leads to increased electrolyte decomposition and serious capacity decay of lithium cobalt oxide materials. It is. Summary of the Invention

[0005] The present invention provides a cathode material, an electrochemical device, and an electronic device, and the cathode material in the present invention is a stable The positive electrode material has a stable crystal structure, and electrochemical devices using the positive electrode material have relatively high capacity and Furthermore, excellent cycle characteristics can be maintained.

[0006] In some embodiments, the present invention provides particles having a P63mc crystal phase structure, A positive electrode material is provided, the particle size distribution curve of which includes a first peak and a second peak. The present invention provides a cathode material made of particles with different particle sizes, while the P63mc phase compound The material has a special oxygen structure, which is stable enough at a high voltage of 4.6V and is gentle on the electrolyte. On the other hand, by designing the particles of the positive electrode material with different particle sizes, It can fully play the role of particles of different sizes, improve the processing properties of materials, and reduce the mixing sedimentation Solves the problem of low compaction density when the temperature is high, and improves rate characteristics In addition, the P63mc crystal phase structure has a unique lithium-deficient structure, which is advantageous for lithium During the lithium absorption and release process, there are lithium vacancies in the crystal structure, and excess Its ability to accommodate lithium ions prevents capacity fade and allows for different particles When particles of a certain diameter are mixed, the kinetics performance of the cathode material is improved. As a result, the P63mc crystal phase structure has a stronger lithium storage capacity and better capacity and better cycle performance.

[0007] In some embodiments, the particle diameter of the particles represented by the first peak is smaller than that of the particles represented by the second peak. Let the peak area of the first peak be S1 and the peak area of the second peak be S2. Then, S1 and S2 satisfy the relational expression 0 < S1 / S2 < 1. In some embodiments S1 and S2 respectively represent the contents of two types of particles with different particle diameters, and 0 < S 1 / S2 < 1 indicates that the percentage of particles with a smaller particle diameter is less than 50%. If the percentage of particles with a smaller particle diameter is too high, the cycle performance may decrease. In some embodiments, when there are no particles with a smaller particle diameter, it is disadvantageous for improving the compression density and is also disadvantageous for improving the kinetics performance of the cathode material.

[0008] In some embodiments, the chemical compositions of the first particles and the second particles are different. The first particles are L i x Na z Co 1-y1 M 1 y1 O2, where 0.6 < x < 0.95, 0 ≤ y1 < 0.15, 0 ≤ z < 0.05, and M 1 is at least one of Al, Mg, Ti, Zr, La, Ca, Ge, N b, Sn, and Y. The second particles are Li x Na z Co 1-y2 M 2 y2 O2, where 0.6 < x < 0.95, 0 ≤ y2 < 0.15, 0 ≤ z < 0 .05, M 2 The alloy contains at least one of Ni, Mn, Zn and Fe. The characteristics of the particles are different. The cycle characteristics of the particles with smaller particle diameters are relatively poor, while the cycle characteristics of the particles with larger particle diameters are relatively poor. Since the rate performance of larger particle sizes is relatively poor, in some embodiments of the present invention, According to the disadvantages of the characteristics of the particles having different particle sizes, the chemical composition of the first particles and the second particles are different. By selecting the corresponding chemical composition, the shortcomings of the properties can be compensated for.

[0009] In some embodiments, the first particles have an average particle size of 3 μm to 12 μm. The average particle size of the second particles is 15 μm to 30 μm. If the average particle size of the first and second particles is too small, the consumption of the electrolyte increases and the cathode material In some other embodiments, the average of the first particles and the second particles is If the average particle size is too large, the rate characteristics may decrease.

[0010] In some embodiments, the particles of the positive electrode material have holes and interstices therein. The particles can make sufficient contact with the electrolyte, and the positive electrode material expands during the charge and discharge process. In this case, the holes and gaps can reduce the internal stress of the positive electrode material, thereby improving the crystal structure. This is advantageous in improving the stability of the structure. In some embodiments, the specific surface area of ​​the positive electrode material is 0. 1m 2 / g~2m 2 / g. If the specific surface area is too small, it is disadvantageous to the rate characteristics. If the specific surface area is too large, the cycle characteristics may deteriorate.

[0011] Some embodiments of the present invention provide a cathode material, the cathode material having a P63mc crystalline phase structure. The positive electrode material has a particle size distribution curve including a first peak and a second peak. The positive electrode material is Li x Na z Co 1-y M y O2, where 0.6 <x<0.95 , 0≦y<0.15, 0≦z<0.05, M is Al, Mg, Ti, Mn, Fe, Ni, Z At least one of N, Cu, Nb, Cr, Y and Zr is contained, and the P63mc crystal structure is The average particle size of the particles having the structure is 3 μm to 30 μm. The pole material may be doped or undoped lithium cobalt oxide. Although doping elements in lithium cobalt oxide can improve the structural stability, However, if the content of the doping element is too high, the capacity loss may be too large, and the present invention It is possible to improve the structural stability while ensuring the capacity within a limited range.

[0012] In some embodiments, the particles of the positive electrode material have holes and interstices therein. The particles can make sufficient contact with the electrolyte, and the positive electrode material expands during the charge and discharge process. In this case, the holes and gaps can reduce the internal stress of the positive electrode material, thereby improving the crystal structure. This is advantageous in improving the stability of the structure. In some embodiments, the specific surface area of ​​the positive electrode material is 0. 1m 2 / g~2m 2 / g. If the specific surface area is too small, it is disadvantageous to the rate characteristics. If the specific surface area is too large, the cycle characteristics may deteriorate.

[0013] Some embodiments of the present invention include a positive electrode, a negative electrode, an electrolyte, and a cell disposed between the positive electrode and the negative electrode. The positive electrode is provided on a current collector and a positive electrode active material is provided on the current collector. The positive electrode active material layer includes any one of the positive electrode materials described above.

[0014] In some embodiments, the positive electrode active material layer of the electrochemical device has a compressed density of 3 g / cm 3 ~4 .35g / cm 3 In some embodiments, the positive electrode material is of two types having different particle sizes. Since the particles have a thickness of 100 μm, it is advantageous to improve the compression density of the positive electrode active material layer. If the degree is too high, the particles may be crushed.

[0015] In some embodiments, the electrolyte includes a compound having 2 to 3 cyano groups. Compounds having one cyano group include dinitrile compounds, trinitrile compounds, ether dinitrile compounds, and It contains at least one of trinitrile compounds and ether trinitrile compounds. In the example, the carbon-nitrogen triple bond of the cyano group has a very high bond energy and is easily oxidized. It is difficult to break down, has a relatively high stability, and the coordination ability of the cyano group is very strong, making it an excellent cathode material. It can coordinate with high valent metal ions in the material, thereby dissolving it into the electrolyte. The amount of cyano groups in a compound having 2 to 3 cyano groups can be reduced. The material of the present invention can more effectively reduce the reaction between the positive electrode and the electrolyte and suppress gas generation. can.

[0016] In some embodiments, the compound having 2-3 cyano groups is glutaronitrile, sucrose, or the like. Kushinonitrile, adiponitrile, 1,3,6-hexanetricarbonitrile, 1,3, 5-Pentanetricarbonitrile, 1,2,3-propanetricarbonitrile, and 1, 2,3-tris(2-cyanoethoxy)propane, The content of compounds having 2 to 3 cyano groups is 0.01 wt% to 15 wt% based on the weight of the material. Some embodiments of the present invention include an electronic device that includes any of the electrochemical devices described above. to provide.

[0017] In some embodiments, the electrolyte is ethylene carbonate, diethyl carbonate, , propylene carbonate, propyl propionate, and vinylene carbonate The organic solvent contains at least one of the above organic solvents, which is compatible with the positive electrode material of the present specification. This creates a synergistic effect and stabilizes the crystal structure, improving cycle characteristics.

[0018] The positive electrode material provided in the embodiment of the present invention includes particles having a P63mc crystal phase structure, and P6 The 3MC crystal phase structure is unique HCP (hexagonal closest packing). g, hexagonal close-packed) oxygen structure, and cycling at high voltages (e.g., 4.6 V or higher) In the present invention, the oxygen structure is stable, it is gentle to the electrolyte, and it has excellent cycle characteristics. Therefore, the presence of the first and second peaks in the particle size distribution curve of the positive electrode material indicates that the positive electrode material It means that two types of particles with different particle sizes are included, thereby improving the processing characteristics of the material. Solving the problem of high compounding settling and low compression density, and improving the P63mc crystal phase structure The battery itself is a lithium-deficient material, and during the charging process it needs to release lithium ions to open up channels. In addition to accommodating the lithium ions released from the battery during the discharge process, It has the electrochemical lithium absorption ability to absorb lithium ions. As a positive electrode material, it has a large When particles and small particles are mixed, the dynamic properties of the cathode material are improved, The material has a stronger lithium absorption ability, and shows better capacity and better cycle characteristics. vinegar. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] The present invention can be realized in various ways. and should not be construed as being limited to the embodiments described herein, but rather These examples are provided to provide a more detailed and complete understanding of the present invention. be.

[0020] In the prior art, lithium cobalt oxide positive electrode materials having the R-3m phase have been used for high voltage applications of 4.6 V or higher. An irreversible phase transition occurs in the crystal structure (from O3 to H1-3, and from H1-3 to O1). This significantly reduces the cycle and safety properties of the material. The ZnO phase is generally used as a cathode material to enhance the structural stability of the R-3m phase lithium cobalt oxide cathode material. Doping with most elements slows down irreversible phase transitions, improving the material's However, this method has a low structural stability when the voltage is greater than 4.6V. The effect of increasing the doping amount is unclear, and the loss of theoretical capacity increases with increasing doping amount. Therefore, in the related art, it is possible to maintain the crystal structure stability at a high voltage of 4.6V or more while still achieving a high efficiency. The amount and cycle characteristics cannot be maintained.

[0021] In order to solve at least some of the above problems, some embodiments of the present invention include a P63 The positive electrode material is a particle having an mc crystal phase structure, and the particle size distribution curve of the positive electrode material is This shows that the positive electrode material contains two types of P with different particle sizes. It can be seen that particles having a 63mc crystal phase structure are included.

[0022] The present invention provides a positive electrode material composed of particles having different particle sizes. On the other hand, P63mc phase compound has a special HCP oxygen structure, is sufficiently stable at a high voltage of 4.6 V, is gentle with the electrolyte, and has excellent cycle characteristics. On the other hand, by designing particles of the positive electrode material having different particle sizes, the roles of particles with different particle sizes can be fully played, the processing characteristics of the material can be improved, and the problem that a high blending sedimentation results in a low compression density can be solved, which is advantageous for improving the rate characteristics. More importantly, the P63mc crystal phase structure has a unique lithium-deficient structure and has lithium vacancies in the crystal structure during the process of lithium release and absorption, and has the ability to accommodate extra lithium ions, so that capacity decay can be prevented. When particles with different particle sizes are mixed, the kinetic characteristics of the positive electrode material are improved, so that the P63mc crystal phase structure has a stronger lithium absorption capacity and exhibits better capacity and better cycle characteristics. That is the case. In some embodiments of the present invention, the particle size of the particles represented by the first peak is smaller than the particle size of the particles represented by the second peak. Let the peak area of the first peak be S1 and the peak area of the second peak be S2. Then, S1 and S2 satisfy the relational expression 0 < S1 / S2 < 1. In some embodiments, S1 and S2 respectively represent the contents of two types of particles having different particle sizes, and 0 < S1 / S2 < 1 represents that the percentage of particles having a smaller particle size is less than 50%. If the percentage of particles having a smaller particle size is too high, the cycle characteristics may decrease. In some embodiments, there are no particles having a smaller particle size.

[0023] In some embodiments of the present invention, the particle size of the particles represented by the first peak is smaller than the particle size of the particles represented by the second peak. Let the peak area of the first peak be S1 and the peak area of the second peak be S2. Then, S1, S2 satisfy the relational expression 0 < S1 / S2 < 1. In some embodiments, S1 and S2 respectively represent the contents of two types of particles having different particle sizes, and 0 < S1 / S2 < 1 represents that the percentage of particles having a smaller particle size is less than 50%. If the percentage of particles having a smaller particle size is too high, the cycle characteristics may decrease. In some embodiments, there are no particles having a smaller particle size. When the peak area of the second peak is S2, S1 and S2 satisfy the relational expression 0 < S1 / S2 < 1. In some embodiments, S1 and S2 respectively represent the contents of two types of particles having different particle sizes, and 0 < S1 / S2 < 1 represents that the percentage of particles having a smaller particle size is less than 50%. If the percentage of particles having a smaller particle size is too high, the cycle characteristics may decrease. In some embodiments, there are no particles having a smaller particle size. and 0 < S1 / S2 < 1 represents that the percentage of particles having a smaller particle size is less than 50%. If the percentage of particles having a smaller particle size is too high, the cycle characteristics may decrease. In some embodiments, there are no particles having a smaller particle size. If the percentage of particles having a smaller particle size is too high, the cycle characteristics may decrease. In some embodiments, there are no particles having a smaller particle size. In some embodiments, there are no particles having a smaller particle size. If the temperature is too low, it is not favorable for improving the compaction density and for improving the dynamic properties of the positive electrode material. .

[0024] In some embodiments of the present invention, the positive electrode material comprises first particles and second particles, the first particles In some embodiments of the present invention, the first particles have a different chemical composition from the second particles. i x Na z Co 1-y1 M 1 y1 O2, where 0.6 <x<0.95、0≦y1 <0.15, 0≦z<0.05, M 1 are Al, Mg, Ti, Zr, La, Ca, Ge, N The second particle contains at least one of Li x Na z Co 1-y2 M 2 y2 O2, where 0.6 <x<0.95、0≦y2<0.15、0≦z<0 .05, M 2 The alloy contains at least one of Ni, Mn, Zn, and Fe. In the embodiment, the properties of particles having different particle sizes are different, and the size of particles having smaller particle sizes is The cycle characteristics of the particles with a large particle size are relatively poor, and the rate characteristics of the particles with a large particle size are relatively poor. Therefore, in some embodiments of the present invention, the chemical composition of the first particles and the second particles are different, By selecting the corresponding chemical composition according to the characteristic defects of particles with different particle sizes, the characteristic defects can be eliminated. For example, the first particles with a small particle diameter are doped with an element that enhances cycle characteristics, and the second particles with a large particle diameter are doped with an element that enhances cycle characteristics. By doping the large second particles with elements that enhance the rate capability, the positive electrode material as a whole The average particle size of the first particles is 3 μm to 12 μm. The average particle size of the first particles is 15 μm to 30 μm. In the case where the average particle diameter of the first particles and the second particles is too small, the consumption of the electrolyte increases, and and is detrimental to the cycle characteristics of the positive electrode material. In some other embodiments, the first particles and If the average particle size of the second particles is too large, the rate characteristics may be deteriorated. In one embodiment, the first particles are particles represented in the first peak and the second particles are particles represented in the second peak. Both the first particle and the second particle have a P63mc crystal phase structure. .

[0025] In some embodiments of the present invention, there are holes and interstices within the particles of the positive electrode material. In some embodiments, the particles have holes and interstices that allow sufficient contact with the electrolyte, and When the positive electrode material expands during charging and discharging, the holes and gaps reduce the internal stress of the positive electrode material. This is advantageous in improving the stability of the crystal structure. In the present invention, the number of holes and gaps on one particle is 50 or less. If the number is too large, the positive electrode material The mechanical strength of the material may become insufficient, making the crystals more susceptible to collapse.

[0026] Some embodiments of the present invention provide a cathode material, the cathode material having a P63mc crystalline phase structure. The positive electrode material is a particle having a particle size distribution curve including a first peak and a second peak. The electrode material is Li x Na z Co 1-y M y O2, where 0.6 <x<0.95、0≦ y<0.15, 0≦z<0.05, M is Al, Mg, Ti, Mn, Fe, Ni, Zn, C At least one of u, Nb, Cr, Y and Zr is contained, and the P63mc crystal phase structure is obtained. The average particle size of the particles is 3μm to 30μm.

[0027] In some embodiments, the positive electrode material is doped or undoped cobalt. Lithium tritium oxide may also be used. Doped lithium cobalt oxide provides a stable structure. It can improve the quality, but if the content of doping elements is too high, the capacity loss will occur. In order to improve the structural stability while ensuring the capacity within the range limited by the present invention, It can be raised.

[0028] In some embodiments, the particle size of the particles affects the structural stability and rate performance of the cathode material. In some embodiments, the first particles have a smaller particle size than the second particles. The second particles, which have a larger particle diameter, have inferior rate characteristics to the first particles. Therefore, the first particle is provided with M, which helps to improve the structural stability of the first particle. 1 The second particle is doped with 2M helps improve the rate characteristics of particles 2 can be doped.

[0029] In some embodiments of the present invention, there are holes and interstices within the particles of the positive electrode material. In some embodiments, the particles have holes and interstices that allow sufficient contact with the electrolyte, and When the positive electrode material expands during charging and discharging, the holes and gaps reduce the internal stress of the positive electrode material. This is advantageous for improving the stability of the crystal structure. In the example, the number of holes and gaps on one particle is 50 or less. If the number is too large, the positive electrode The mechanical strength of the material may become insufficient, making the crystal collapse more likely to occur.

[0030] In some embodiments of the present invention, the specific surface area of ​​the positive electrode material is less than 0.1 m 2 / g~2m 2 / g In some embodiments, the specific surface area is 2 m 2 If it exceeds / g, electrolyte consumption This accelerates the oxidation process, which reduces the stability of the crystal structure and may lead to a deterioration in cycle characteristics. On the other hand, the specific surface area of ​​0.1 m 2 If the ratio is less than 1 / g, the rate characteristics are poor. There is a risk of this happening.

[0031] Some embodiments of the present invention further include a positive electrode, a negative electrode, an electrolyte, and a battery disposed between the positive electrode and the negative electrode. a separator having a positive electrode disposed on the current collector; and a positive electrode active material layer comprising the positive electrode material of any of the above embodiments. .

[0032] In some embodiments of the present invention, the positive electrode active material layer of the electrochemical device has a compressed density of 3 g / cm. m 3 ~4.35g / cm 3 In some embodiments, the positive electrode material has different particle sizes. Since there are two types of particles, it is advantageous to increase the compression density of the positive electrode active material layer. In one embodiment, the compressed density of the positive electrode active material layer when compressed at a pressure of 150 MPa is 3. .80g / cm 3 The above is the compression ratio of the positive electrode active material layer when compressed at a pressure of 250 MPa. Density is 4g / cm 3 The pressure of the positive electrode active material layer when compressed at a pressure of 500 MPa is equal to or greater than the pressure of the positive electrode active material layer. The shrink density is 4.2g / cm 3 (c) The electrochemical device has a discharge capacity of 200 mAh. If the electrochemical device is 0.1 μm / g or more, cycle the electrochemical device 20 times at a rate of 1 C, and In some embodiments, the increase in DC resistance is 2% or less. Since the increase rate of the DC resistance after the cycle is 2% or less, the positive and negative electrodes of the electrochemical device of the present invention can be used. The polar material has better structural stability and no obvious structural changes occur during cycling. It can be seen that the change in the temperature does not result in a clear increase in the DC resistance.

[0033] In some embodiments of the present invention, the electrolyte contains a compound having 2 to 3 cyano groups. Compounds having 2 to 3 cyano groups are dinitrile compounds, trinitrile compounds, ether compounds, etc. The compound contains at least one of a trinitrile compound and an ether trinitrile compound. In some examples, the bond energy of the carbon-nitrogen triple bond of the cyano group is very high. , it is not easily oxidized, has a relatively high stability, and the coordination ability of the cyano group is very strong. It can coordinate with high-valence metal ions in the positive electrode material. Compared with monocyano compounds, it has 2-3 cyano groups, which reduces the decomposition of the The compound having the above structure can effectively reduce the reaction between the positive electrode and the electrolyte and suppress gas generation. can be done.

[0034] In some embodiments of the present invention, the compound having 2-3 cyano groups is glutaronitate. aryl, succinonitrile, adiponitrile, 1,3,6-hexanetricarbonitrile, 1,3,5-pentanetricarbonitrile, 1,2,3-propanetricarbonitrile, and 1,2,3-tris(2-cyanoethoxy)propane The content of the compound having 2 to 3 cyano groups is 0.01 wt% based on the weight of the electrolyte. ~15wt%.

[0035] In some embodiments, the positive electrode current collector may be an Al foil, but it is generally used in the art. Of course, other positive electrode current collectors used in the present invention may be used. In some embodiments, the thickness of the positive electrode current collector may be 1 μm to 200 μm. In some cases, the positive electrode active material layer may be applied to only a partial area of ​​the positive electrode current collector. In the embodiment, the thickness of the positive electrode active material layer may be 10 μm to 500 μm. Please note that these are examples only and other suitable thicknesses may be used.

[0036] In some embodiments, the separator is made of polyethylene, polypropylene, polyvinyl chloride, or polyisocyanate. At least one of the following: ethylenediamine, polyethylene terephthalate, polyimide, and aramid For example, polyethylene includes high density polyethylene, low density polyethylene, and ultra- At least one selected from polyethylene and high molecular weight polyethylene. Polypropylene has excellent short circuit prevention and shutdown effect. In some embodiments, the thickness of the separator is about 5 μm. The range is between 100 and 500 μm.

[0037] In some embodiments, the surface of the separator further comprises at least one The substrate may include a porous layer disposed on the surface, the porous layer including inorganic particles and a binder. The particles are aluminum oxide (Al2O3), silicon oxide (SiO2), magnesium oxide Magnesium oxide (MgO), titanium oxide (TiO2), hafnium dioxide (HfO2), tin oxide (S nO2), cerium oxide (CeO2), nickel oxide (NiO), zinc oxide (ZnO), Calcium oxide (CaO), zirconium oxide (ZrO2), yttrium oxide (Y2O 3), silicon carbide (SiC), boehmite, aluminum hydroxide, magnesium hydroxide, At least one selected from calcium hydroxide and barium sulfate. In an embodiment, the pores of the separator have a diameter in the range of about 0.01 μm to 1 μm. The binder is polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene. Polymers, polyamides, polyacrylonitrile, polyacrylic esters, polyacrylic acids , polyacrylate, sodium carboxymethylcellulose, polyvinylpyrrolidone, Polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene and polyhe The porous separator surface is at least one selected from the group consisting of fluoropropylene, fluoroisopropyl ether, fluoroisopropyl ether, and fluoroisopropyl ether. The layer enhances the heat resistance, oxidation prevention and electrolyte wettability of the separator, and provides a good interface between the separator and the electrodes. This can strengthen the adhesion to the piece.

[0038] In some embodiments of the present invention, the electrochemical device is of a rolled or stacked type.

[0039] In some embodiments, the electrochemical device comprises a lithium ion battery, which In some embodiments, the electrochemical device may further include an electrolyte. The electrolyte may be one or more of a gel electrolyte, a solid electrolyte, and an electrolyte solution. It contains a lithium salt and a non-aqueous solvent. The lithium salt is LiPF6, LiBF4, LiAsF6, LiClO4, LiB(C6H5)4, LiCH3SO3, LiCF3SO3, LiN( SO2CF3)2, LiC(SO2CF3)3, LiSiF6, LiBOB and Diflu For example, it is possible to provide high ionic conductivity, and LiPF6 is used as the lithium salt to improve cycle characteristics.

[0040] The non-aqueous solvent may be a carbonate ester compound, a carboxylate compound, an ether compound, or any other organic solvent. The solvent may be an organic solvent or a combination thereof.

[0041] Carbonate compounds include chain carbonate compounds, cyclic carbonate compounds, and fluorocarbon compounds. It may be an acid ester compound or a combination thereof.

[0042] Examples of chain carbonate ester compounds are diethyl carbonate (DEC), dimethyl carbonate, Dimethyl ether carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (M PC), Ethyl propyl carbonate (EPC), Ethyl methyl carbonate (MEC) and combinations thereof. Specific examples of the cyclic carbonate ester compound include ethylene carbonate, Carbonate (EC), Propylene Carbonate (PC), Butylene Carbonate (BC), fluorocarbonate (VEC), fluoroethylene carbonate (VEC), or a combination thereof. Examples of ester compounds are fluoroethylene carbonate (FEC), 1,2-difluoroethylene carbonate (1,2-difluoroethylene carbonate), 1,1-Difluoroethylene carbonate, 1,1,2-Trifluoroethylene carbonate Fluoroethylene carbonate, 1,1,2,2-tetrafluoroethylene carbonate , 1-fluoro-2-methylethylene carbonate, 1-fluoro-1-methylethylene Carbonate, 1,2-difluoro-1-methylethylene carbonate, 1,1,2- Trifluoro-2-methylethylene carbonate, Trifluoromethylethylene carbonate or a combination thereof.

[0043] Examples of carboxylic acid ester compounds are methyl acetate, ethyl acetate, n-propyl acetate, acetic acid tert-Butyl, methyl propionate, ethyl propionate, propyl propionate, γ-butyrolactone, decanolide, valerolactone, mevalonolactone, caprolactone , methyl formate, or a combination thereof.

[0044] Examples of ether compounds are dibutyl ether, tetraethylene glycol dimethyl ether, Diethylene glycol dimethyl ether, 1,2-dimethoxyethane, 1,2-diethylene ethoxyethane, ethoxymethoxyethane, 2-methyltetrahydrofuran, tetrahydro furan or a combination thereof.

[0045] Examples of other organic solvents are dimethyl sulfoxide, 1,2-dioxolane, sulfolane, methyl Thilsulfolane, 1,3-dimethyl-2-imidazolidinone, N-methyl-2-pyrrolide Formamide, dimethylmethylamide, acetonitrile, trimethyl phosphate, phosphate triethyl, trioctyl phosphate, and phosphate esters or combinations thereof.

[0046] Embodiments of the present invention further provide electronic devices that include the electrochemical devices described above. The electrochemical device is not particularly limited and may be used in any electronic device known in the prior art. In some embodiments, the electrochemical device of the present application is a Input type computers, mobile computers, e-book players, mobile phones, Band-type facsimile, portable copier, portable printer, stereo headset, video Recorders, LCD TVs, portable cleaners, portable CD players, mini discs , walkie-talkies, electronic notebooks, calculators, memory cards, portable tape recorders , radio, backup power supply, motor, automobile, motorcycle, auxiliary bicycle, bicycle , lighting equipment, toys, game consoles, clocks, power tools, flashlights, cameras, large household storage This includes, but is not limited to, storage batteries, and lithium-ion capacitors. .

[0047] Some embodiments of the present invention further comprise a cathode material prepared using the cathode materials in the above embodiments. A method for preparing a material is provided, the method comprising the steps of:

[0048] (1) Li x Na z Co 1-y M y O2 was prepared, where 0.6 <x<0.95、0≦ y<0.15, 0≦z<0.05, M is Al, Mg, Ti, Mn, Fe, Ni, Zn, C At least one element selected from the group consisting of U, Nb, Cr and Zr.

[0049] (2) M with different particle sizes obtained by the liquid phase precipitation method and the sintering method 1 The element was doped (Co 1- y1 M 1 y1 )3O4 and M 2 The element was doped (Co 1-y2 M 2 y2 )3O4 precursor Prepare the body: Soluble cobalt salts (e.g., cobalt chloride, cobalt acetate, cobalt sulfate) , cobalt nitrate, etc.) and M salt (e.g., sulfate, etc.) in a molar ratio of Co to M of (1-y1) y1 and (1-y2):y2 in a solvent (e.g., deionized water), and Precipitants (e.g., sodium carbonate, sodium hydroxide) at concentrations of 1 / L to 3mol / L and A complexing agent (e.g., an aqueous ammonia solution) is added, and the molar ratio of the complexing agent to the precipitating agent is 0.1 to 1. and then adjusting the pH value (for example, adjusting the pH value to 5 to 9) to cause precipitation. The precipitate is sintered in air at 400℃-800℃ for 5h-20h, and the sintered product is polished and then processed into different Particle size M 1 The element was doped (Co 1-y1 M 1 y1 )3O4 and M 2 The element Doped (Co 1-y2 M 2 y2 )3O4 precursor is obtained. M 1 are Al, Mg, and T At least one of i, Zr, La, Ca, Ge, Nb, Sn and Y, 2 teeth It contains at least one of Ni, Mn, Zn and Fe.

[0050] (3) Na by solid-phase sintering m Co 1-y M y Synthesize O2: As a precursor, M 1 The element is Grouped (Co 1-y1 M 1 y1 )3O4 and M 2 The element was doped (Co 1-y2 M 2 y2 )3O4 powder and Na2CO3 powder with a molar ratio of Na to Co of 0. Mix the powders in a ratio of 7:1 to a maximum of 0.74:1. Place the powders in an oxygen gas atmosphere until they are uniform. Sintering was performed at 700℃~1000℃ for 36h~56h in an atmospheric condition, and the result was a Na alloy with P63mc structure. mCo 1-y1 M 1 y1 O2 and Na m Co 1-y2 M 2 y2 O2 is obtained, where 0 .6 < m < 1.

[0051] (4) Synthesize the Li x Na z Co 1-y M y O2 cathode material by ion exchange method: Na m Co 1-y1 M 1 y1 O2 or Na m Co 1-y2 M 2 y2 O2, and a lithium -containing molten salt (such as lithium nitrate, lithium chloride, lithium hydroxide, etc.) are mixed until the molar ratio of Na to Li becomes uniform at a ratio of 0.01 - 0.2, and reacted at 200°C - 400°C in an air atmosphere for 2 h - 8 h. The product is washed several times with deionized water to remove the molten salt , and then the powder is dried to obtain Li x Na z Co 1-y1 M 1 y1 O2, where 0.6 < x < 0.95, 0 ≤ y1 < 0.15, 0 ≤ z < 0.05, and the second particles contain Li Na x Na z Co 1-y2 M 2 y2 O2, where 0.6 < x < 0.9 5, 0 ≤ y2 < 0.15, 0 ≤ z < 0.05.

[0052] (5) Li x Na z Co 1-y1 M 1 y1 O2 and Li xNa z Co 1-y2 M 2 y2 O2 and are mixed in a certain ratio, where Li x Na z Co 1-y2 M 2 y2 The number of O2 is Li x Na z Co 1-y1 M 1 y1 Less than O2.

[0053] In the following, some examples and comparative examples will be given to further explain the present invention. Here, a lithium-ion battery is taken as an example.

[0054] Preparation of the positive electrode piece: The positive electrode material, conductive carbon black as a conductive agent, and poly(ethylene glycol) as a binder Vinylidene fluoride was mixed with N-methylpyrrolidone (NMP) in a weight ratio of 97:1.4:1.6. The aluminum foil was used as the positive electrode current collector, and the positive electrode strip was made of 100% aluminum. The slurry was applied to the positive electrode current collector at a coating weight of 17.2 mg / cm 2 Then, drying and cold rolling After cutting, a positive electrode piece was obtained.

[0055] Preparation of negative electrode pieces: The negative electrode material was artificial graphite. Negative electrode material, acrylic resin, conductive carbon Black and sodium carboxymethylcellulose in a weight ratio of 94.8:4.0:0.2 The silica gel is dissolved in deionized water in a ratio of 1.0:1.0 to form a negative electrode active material layer slurry. The weight percentage of the raw material was 10%. A copper foil with a thickness of 10 μm was used as the negative electrode current collector, and the negative electrode slurry was was applied onto the negative electrode current collector, with the coating weight being 6.27 mg / cm 2 The water content of the negative electrode piece is 3 The negative electrode active material layer was obtained by cutting the negative electrode piece. was obtained.

[0056] Preparation of the separator: The separator substrate is polyethylene (PE) with a thickness of 8 μm. A 2 μm layer of aluminum oxide ceramic is applied to both sides of the substrate. The ceramic layer is then coated with a binder, polyvinylidene fluoride (PVDF), on both sides of the ceramic layer. ) 2.5 mg was applied and allowed to dry.

[0057] Preparation of electrolyte: In an environment with a water content of less than 10 ppm, lithium hexafluorophosphate and nonaqueous electrolyte were used. Organic solvent (weight ratio: ethylene carbonate (EC):diethyl carbonate (DEC) : Propylene carbonate (PC): Propyl propionate (PP): Vinylene carbonate The electrolyte was formed by mixing 100% ethyl alcohol (VC) and 100% ethyl alcohol (V) in a weight ratio of 8:92. Successful.

[0058] Preparation of Lithium-Ion Batteries: The separator acts as an insulator between the positive and negative electrode pieces. The positive electrode piece, the separator, and the negative electrode piece were stacked in this order and wound up to obtain an electrode assembly. The three-dimensional object is placed on the exterior aluminum plastic film, and after removing moisture at 80℃, The electrolyte is poured, packaged, and then subjected to formation, degassing, and After going through a process flow including trimming, a lithium-ion battery was obtained.

[0059] The preparation steps of the lithium ion batteries of the Examples and Comparative Examples are similar. The only difference is the positive electrode material used. The specific positive electrode materials used are listed in Table 1 below. ~As shown in Table 8.

[0060] The method for measuring each parameter of the present invention will be described below.

[0061] Particle volume distribution measurement: An appropriate amount of powder is dispersed by ultrasonic waves, and the dispersion is measured by a laser particle size measuring device (Mastersize r 3000) and the measurement method is particle size distribution laser diffraction method GB / T19077 -2016, 1, measurement range is 0.02μm~2000μm(MS2000), 0 .01μm~3500μm (MS3000),2 and the detection limit was 20nm. Finally, a volume distribution curve of the powder was obtained. Note that the average particle size in the present invention is the average particle size of one sample. The particle size distribution percentage corresponds to 50% of the cumulative particle size distribution percentage in the volumetric particle size distribution. Refers to the diameter of the tube.

[0062] Capacity retention measurement: Charge and discharge the battery for the first time at 25℃, and discharge the battery at 0.5C (i.e., the theoretical capacity is fully discharged within 2 hours). The battery was charged at a constant current of 1000 V (the current value that discharges the battery to 1000 V) until the upper limit voltage reached 4.8 V. Discharge at a constant current of 0.5C until the final voltage is 3V. The initial discharge capacity was recorded, and the battery was then charged and discharged 100 times. The discharge capacity of the lithium-ion battery was recorded at the 100th cycle. The capacity retention rate at the 1st cycle was calculated.

[0063] 100 cycle capacity retention rate = 100th cycle discharge capacity / first cycle discharge capacity × 100% .

[0064] Hole and Gap Measurement: The cathode material was processed using an ion milling machine (JEOL-IB-09010CP) and the cross section The cross section was photographed with a scanning electron microscope at a magnification of 5.0K or higher. In the cross-sectional image, holes and gaps are seen, and in the cross-sectional image of the particle, the color is different from the surroundings. The closed areas were holes and gaps.

[0065] Requirements for selecting holes: Holes that meet the counting requirements must be located along the longest axis of a single particle. The ratio of the longest axis of the closed region to the longest axis of the closed region is between 2% and 10%, and the longest axis of the closed region is the maximum The difference in minor axis is less than 0.5 micrometers.

[0066] Requirements for selecting gaps: A gap that satisfies the counting requirements must be the smallest gap between the particles in a single particle. The ratio of the longest axis of the occluded area to the major axis is 70% or more.

[0067] How to select the long and short axes: Connect any two points of the closed curve and choose the one with the longest distance as the longest axis. The axis with the shortest distance was determined as the shortest axis.

[0068] A closed area is an area surrounded by a closed curve in a figure, and any part of the inside of the closed area A line segment connecting a point in the region to any point outside the region intersects the boundary of the region.

[0069] Elemental composition determination: The elemental composition of the positive electrode material powder was measured using an iCAP7000 ICP measurement device.

[0070] The electrode pieces with the positive electrode material on them are dissolved in NMP, filtered, the powder is dried, and then Elemental composition measurements were performed using a CAP7000 ICP analyzer.

[0071] X-ray diffraction measurement: XRD diffraction patterns of cathode materials measured using Bruker D8 ADVANCE If the powder cannot be removed, dissolve the positive electrode pieces in NMP, filter, and remove the powder. The bodies were dried and the powder was measured by XRD.

[0072] Specific surface area (BET) measurement method: Measurement device: BSD-BET400, measurement process: The pipe is placed in a gas system filled with N2, and the surface of the material is physically adsorbed at the temperature of liquid nitrogen. When the physical adsorption is in equilibrium, the adsorption pressure and the flow rate of the adsorption gas are measured. By determining the surface area of ​​the material, the amount of monolayer adsorption of the material can be calculated, and thus the specific surface area of ​​the sample can be calculated. I calculated it.

[0073] Compression density measurement: Lithium-ion battery is placed at 0 SOC% (SOC: State Of Charge) ge, state of charge), disassemble the battery, clean it, dry it, and weigh it using an electronic balance. A positive electrode piece (a positive electrode current collector coated with a positive electrode active material layer on both sides) having a certain area A is weighed. Weigh it, call its weight W1, and measure the positive electrode using a one-thousandth micrometer. The thickness T1 was measured. The positive electrode active material layer was washed off with a solvent, dried, and the weight of the positive electrode current collector was Measure and call it W2, and use a ten-thousandth micrometer to measure the thickness of the positive electrode current collector. The weight W of the positive electrode active material layer arranged on one side of the positive electrode current collector was measured using the following formula: 0 and thickness T0, and the compressed density of the positive electrode active material layer were calculated: W0 = (W1 - W2) / 2 T0=(T1-T2) / 2 Compressed density = W0 / (T0 x A).

[0074] [Table 1-1] [Table 1-2]

[0075] From Table 1, the total initial discharge capacity and cycle capacity in Examples 1-1 to 1-17 It can be seen that the performance is superior to that of Comparative Examples 1-1 to 1-8. Li with 3mc crystal phase structure a1 Na c1 Co 1-b1 M 1 b1 O2 and Li a2 Na c2 C o 1-b2 M 2 b2 O2 is also included, and Li a1 Na c1 Co 1-b1 M 1 b1 O 2 and Li a2 Na c2 Co 1-b2 M 2 b2 When the size of O2 particles is different, It can be seen that the capacitance and cycle capacity can be increased. In one embodiment, the positive electrode material includes particles having a P63mc crystal phase structure, and the positive electrode The particle size distribution curve of the material is limited to include a first peak and a second peak.

[0076] Comparing Examples 1-1 to 1-17 with Comparative Examples 1-9 and 1-10, The size of the particles is in the range of 3 μm to 12 μm, and the size of the second particles is in the range of 15 μm to 30 μm. m, the initial discharge capacity of the lithium-ion battery is 239 mAh / g or more. and the capacity retention rate at 100 cycles is 88% or more, When the size of the second particles is 13 μm or more and the size of the second particles is 32 μm or more, the initial discharge capacity and It can be seen that the cycle capacity retention rate decreases. Therefore, in some examples, The average particle size of the first particles is 3 μm to 12 μm, and the average particle size of the second particles is 15 μm to 30 μm. m.

[0077] Comparing Examples 1-1 to 1-17, Example 1-1 is M 1 Or M 2 Dope it up On the other hand, all of Examples 1-2 to 1-17 were doped, and Example 1-2 The initial discharge capacity and 100 cycle capacity retention rate in Examples 1-17 are 1-1. Therefore, in some embodiments of the present invention, The pole material is M 1 Or M 2 It has.

[0078] From Examples 1-18 to 1-19, Zn was used in Example 1-18, and Zn was used in Example 1-19. The Al-doped nanoparticles have large and small particles with similar chemical composition. In order to measure the initial discharge capacity and the 100th cycle capacity in Examples 1-18 to 1-19, It can be seen that the retention rates are all superior to those of Example 1-1. In some embodiments, the particle size distribution curve of the positive electrode material includes a first peak and a second peak. There are.

[0079] In the examples and comparative examples shown in Table 2, the positive electrode material used was Li x Na z Co 1-y M y O2, and the crystal phase of the positive electrode material in each of the examples and comparative examples in Table 2 The structures of both were P63mc.

[0080] [Table 2]

[0081] Comparing Example 2-1 with Comparative Examples 2-1 to 2-3, it is found that there are no holes or gaps in the positive electrode material. In contrast to Comparative Example 2-3, when the positive electrode material has either holes or gaps, the initial discharge capacity and The capacity retention rate at 100 cycles can be improved, and the positive electrode material has holes and gaps at the same time. In this case, the lithium-ion battery has a higher initial discharge capacity and a higher 100-cycle capacity retention rate. Therefore, in some embodiments of the present invention, the inside of the particles of the positive electrode material The presence of holes and gaps is limited.

[0082] In the examples and comparative examples shown in Table 3, the positive electrode material used was Li x Na z Co 1-y M y O2, and the crystal phase of the positive electrode material in each of the examples and comparative examples in Table 3. The structures of both were P63mc.

[0083] [Table 3]

[0084] Comparing Example 3-1, Example 3-2, Comparative Example 3-1 and Comparative Example 3-2, the positive electrode material Specific surface area is 2m 2 When the content exceeds 1 / g, the initial discharge capacity of the lithium ion battery is small, and The 100-cycle capacity retention rate is low, and the specific surface area of ​​the positive electrode material is 2m 2 / g or less, lithium The initial discharge capacity of the lithium-ion battery is high, and the capacity retention rate over 100 cycles is good. Therefore, in some embodiments of the present invention, the specific surface area of ​​the positive electrode material is 0.1 m 2 / g~2m 2 / g.

[0085] In the examples and comparative examples shown in Table 4, the positive electrode material used was Li x Na z Co 1-y M y O2, and the crystal phase of the positive electrode material in each of the examples and comparative examples in Table 4. The structure of each was P63mc. The main peak range in Table 4 is the X of the positive electrode material. This refers to the diffraction angle of the diffraction peak with the strongest intensity in the X-ray diffraction pattern, and is the half-maximum full-width in Table 4. The width refers to the full width at half maximum of the main diffraction peak.

[0086] [Table 4]

[0087] Comparing Example 4-1, Example 4-2, Comparative Example 4-1 and Comparative Example 4-2, When the focus range is between 18° and 19°, the FWHM is shorter than when the FWHM is greater than 0.5°. When the width is within the range of 0° to 0.5°, the initial discharge capacity and 100 The cycle capacity retention rate is high in both cases, and the intensity is the highest in the X-ray diffraction pattern of the positive electrode material. The diffraction angles of the strong diffraction peaks are in the range of 18° to 19°, and the half-angle of the strongest diffraction peak is The full range of values ​​is in the range of 0° to 0.5°.

[0088] In the examples and comparative examples shown in Table 5, the positive electrode material used was Li x Na z Co 1-y M y O2, and the crystal phase of the positive electrode material in each of the examples and comparative examples in Table 5. The structures of both were P63mc.

[0089] [Table 5]

[0090] Comparing Examples 5-1 to 5-6 and Comparative Examples 5-1 and 5-2, The initial discharge capacity and 100 cycle capacity retention rate of Examples 5-1 to 5-6 are all comparative examples. It can be seen that the compression density of the positive electrode active material layer is higher than that of Comparative Example 5-1 and Comparative Example 5-2. g / cm 3 ~4.35g / cm 3 If so, the discharge characteristics and cycle of the lithium-ion battery This is advantageous for improving the characteristics of the film.

[0091] [Table 6]

[0092] Comparing Examples 7-1 to 7-8 with Comparative Examples 7-1 and 7-2, A compound having 2-3 cyano groups is added to the electrolyte of a lithium-ion battery, and then 2-3 The mass content of the compound having a cyano group is controlled within the range of 0.01wt% to 15wt%. In this case, the initial discharge capacity and 100 cycle capacity retention rate of a lithium-ion battery can be improved. This can be done.

[0093] The foregoing is merely illustrative of the preferred embodiments of the present invention and the principles of the technology applied thereto. It should be understood by those skilled in the art that the scope of the disclosure contained in the present invention does not include any particular combination of the above technical features. The technical solution is not limited to a combination of the above technical features or any combination of features equivalent thereto. Other technical solutions that are combinations of the above features and similar features disclosed in the present invention are also included. It is a technical proposal that is a modification of the technical features having the same functions as those of the prior art.

Claims

1. P6 ３ Contains particles having an mc crystalline phase structure, The particle size distribution curve of the positive electrode material includes a first peak and a second peak. , positive electrode material.

2. The particle size of the particles represented by the first peak is smaller than the particle size of the particles represented by the second peak. If the peak area of ​​the first peak is S1 and the peak area of ​​the second peak is S2, , S1, S2 satisfy the relation 0<S1 / S2<1. Positive electrode material.

3. the positive electrode material includes first particles and second particles; The first particles are Li ｘ Na ｚ Co １－ｙ１ M １ ｙ１ O ２ where 0.6<x< 095、0≦910015、0≦9005、0 １ YN、N、S、2、4 At least one of a, Ca, Ge, Nb, Sn, and Y is included; The second particles are Li ｘ Na ｚ Co １－ｙ２ M ２ ｙ２ O ２ where 0.6<x< 0.95, 0≦y2<0.15, 0≦z<0.05, M ２ is Ni, Mn, Zn and Fe The positive electrode material according to claim 1 , comprising at least one of the following:

4. The first particles have an average particle size of 3 μm to 12 μm. Positive electrode material.

5. The second particles have an average particle size of 15 μm to 30 μm. The cathode material.

6. The positive electrode according to claim 1, characterized in that there are holes and gaps inside the particles of the positive electrode material. material.

7. The specific surface area of ​​the positive electrode material is 0.1 m ２ / g to 2m ２ / g.

2. The positive electrode material according to claim 1.

8. P6 ３ Contains particles having an mc crystalline phase structure, The particle size distribution curve of the positive electrode material includes a first peak and a second peak; The positive electrode material is Li ｘ Na ｚ Co １－ｙ M ｙ O ２ where 0.6<x<0.9 5, 0≦y<0.15, 0≦z<0.05, M is Al, Mg, Ti, Mn, Fe, Ni, It is characterized by containing at least one of Zn, Cu, Nb, Cr, Y and Zr. Positive electrode material.

9. P6 ３ It is particularly noted that the average particle size of particles having the mc crystal phase structure is 3 μm to 30 μm. The positive electrode material according to claim 8 .

10. A battery comprising a positive electrode, a negative electrode, an electrolyte, and a separator disposed between the positive electrode and the negative electrode; The positive electrode includes a current collector and a positive electrode active material layer disposed on the current collector, An electrochemical device, characterized in that the layer contains the positive electrode material according to any one of claims 1 to 9. Place.

11. The compressed density of the positive electrode active material layer is 3 g / cm ３ ~4.35g / cm ３ The present invention is characterized in that The electrochemical device according to claim 10 .

12. The electrolyte contains a compound having 2 to 3 cyano groups, and the weight of the electrolyte is The content of the compound having 2 to 3 cyano groups is 0.01 wt % to 15 wt %.

11. The electrochemical device according to claim 10 .

13. The compounds having 2 to 3 cyano groups include dinitrile compounds, trinitrile compounds, acetonitrile compounds, and the like. The present invention relates to a method for producing a tertiary nitrile compound, and a method for producing the same. The electrochemical device according to claim 12 .

14. The compounds having 2 to 3 cyano groups are glutaronitrile, succinonitrile, adiponitrile, Nitrile, 1,3,6-Hexanetricarbonitrile, 1,3,5-Pentanetricarbonitrile nitrile, 1,2,3-propanetricarbonitrile, and 1,2,3-tris(2-cyclohexyl) 13. The method according to claim 12, characterized in that it contains at least one of the following: The electrochemical device described herein.

15. An electronic device comprising the electrochemical device according to any one of claims 10 to 15. Place.

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