3382results about "Electrolytes" patented technology

A solid electrolyte includes: LiaAbEc(SO4)dJeXfHh, A is selected from alkaline earth metals and alkali metals other than Li, E is selected from Al, Ga, In, Sc, Y, Ti, Zr, Hf, and lanthanides, J is selected from OH, BO2, BO3, BO4, B3O6, B4O7, CO3, NO3, AlO2, SiO3, SiO4, Si2O7, Si3O9, Si4O11, Si6O18, PO3, PO4, P2O7, P3O10, SO3, SO5, S2O3, S2O4, S2O5, S2O6, S2O7, S2O8, BF4, PF6, BOB, (COO)2, N, AlCl4, CF3SO3, CH3COO, CF3COO, OOC—(CH2)2—COO, OOC—CH2—COO, OOC—CH(OH)—CH(OH)—COO, OOC—CH(OH)—CH2—COO, C6H5SO3, OOC—CH═CH—COO, OOC—CH═CH—COO, C(OH)(CH2COOH)2COO, AsO4, BiO4, CrO4, MnO4, PtF6, PtCl6, PtBr6, PtI6, SbO4, SeO4, TeO4, HCOO, and O, X is selected from F, Cl, Br, and I, 0.5≤a<6, 0≤b<6,0<c<2,0.1<d≤6.0, 0<e≤6.0, 0<f≤6.1, and 0≤h≤0.2, and a peak is observed at a diffraction angle 2θ=22.3°±1.0° in an X-ray diffraction pattern in which Cu-Kα is used as a line source.

The invention relates to the technical field of batteries, in particular to a battery. Comprising a positive plate and electrolyte, the positive plate comprises a positive current collector and a coating positioned on the surface edge of at least one side of the positive current collector along the length direction; the coating comprises filling particles, and the filling particles comprise at least one of inorganic particles and nitrogen-containing particles; the electrolyte comprises non-fluorinated cyclic carbonate and fluorinated ethyl acetate; the non-fluorinated cyclic carbonate comprises propylene carbonate and optional ethylene carbonate; on the basis of the total mass of the electrolyte, the content ratio C1 of the non-fluorinated cyclic carbonate is smaller than or equal to 25%, the content ratio C11 of the propylene carbonate is 3.1%-24.9%, the content ratio C12 of the ethylene carbonate is 0%-5%, and the content ratio C2 of the fluorinated ethyl acetate is 20.2%-70%. The battery provided by the invention can improve the problem of lithium precipitation under low-temperature discharge, and has relatively good short-circuit safety performance and relatively low high-temperature gas production rate.

The invention relates to a bismuth-containing modified electrolyte, an all-vanadium redox flow battery and a preparation method and application of the all-vanadium redox flow battery, and belongs to the technical field of all-vanadium redox flow batteries. The bismuth-containing modified electrolyte comprises a vanadium electrolyte, bismuth salt is added into the vanadium electrolyte to serve as a catalyst, and a hydroxyl carboxylic acid complexing agent is added; the molar ratio of the bismuth salt to the hydroxycarboxylic acid complexing agent is (6-8): (0.6-0.8). According to the invention, the catalyst and the complexing agent are added into the electrolyte, the Bi elementary substance is deposited on the electrode through the charging process of the battery, the active sites of the electrode are increased, and the energy efficiency of the battery is improved. Meanwhile, the catalyst can improve the capacity retention ratio of the flow battery, greatly simplify the process steps and reduce the cost.

The invention belongs to the technical field of design and preparation of solid electrolyte materials, and particularly relates to a LiBH4-based composite solid electrolyte material and a preparation method thereof.The LiBH4-based composite solid electrolyte material is obtained by performing high-energy ball milling on a mixture of LiBH4 and one or two metal halides MX2 in a certain molar ratio in an argon atmosphere; m is Mg, Zn, Ni or Bi; x is F, Cl, Br or I. According to the LiBH4 composite solid electrolyte prepared by the preparation method disclosed by the invention, the ionic conductivity at room temperature is improved to 10 <-4 > S cm <-1 > or above, and the ion diffusion activation energy is only 0.16 eV; the process is simple, the preparation time is short, the repeatability is high, no pollution is caused to the environment, and the industrial production requirement is met, so that the all-solid-state lithium ion battery electrolyte is expected to realize commercialized application.

The invention relates to the technical field of batteries, in particular to silicon carbon particles, a negative plate and a battery. The invention provides a silicon-carbon particle. The surface of the silicon-carbon particle is provided with a concave part; the number N of the concave parts on the surfaces of the silicon carbon particles is greater than or equal to 1; the diameter of the concave part is 0.05 [mu] m-5 [mu] m; the depth of the recessed part is 10 nm to 5 [mu] m. The sunken parts are arranged on the surfaces of the silicon-carbon particles, so that the cycle stability and the expansion performance of the silicon-based negative electrode material are improved.

The invention discloses a preparation method and application of a single ion conductor composite binder. The binding agent is prepared by carrying out compound modification on a copolymer of butyl acrylate and 2-acrylamido-2-lithium methylpropanesulfonate and polyisobutene. The binder is mainly characterized in that firstly, the binder can be completely dissolved in a toluene non-polar solvent, and the problem that a traditional binder is incompatible with sulfide electrolyte is solved; and secondly, due to the unique molecular structure design, the adhesive has excellent adhesive property and ionic conductivity, and the interface impedance can be remarkably reduced. A butyl acrylate flexible chain segment provides elastic support, and a sulfonate group of 2-acrylamido-2-lithium methylpropanesulfonate and the surfaces of sulfide particles form strong chemical bonding, so that the binding force with electrolyte is enhanced. The binder is simple in preparation process, controllable in cost and suitable for large-scale production, and an important material solution is provided for promoting industrialization of sulfide all-solid-state batteries.

The invention relates to the technical field of new energy battery materials, in particular to a surface-coated sulfide solid electrolyte as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing and stirring a sulfide solid electrolyte and a first solvent to obtain a first mixed solution; mixing and stirring nanoparticles with oxygen-containing functional groups and a second solvent to obtain a second mixed solution; adding the second mixed solution into the first mixed solution, and stirring to obtain a third mixed solution; and carrying out vacuum drying on the third mixed solution to obtain the surface-coated sulfide solid electrolyte. The sulfide solid electrolyte is subjected to surface particle coating through simple mixing and vacuum drying, oxygen-containing functional groups are attached to the surfaces of the particles, so that the material is more oxygen-loving, the air stability of the sulfide solid electrolyte is improved, and the material still keeps high ionic conductivity and has good electrochemical performance. And moreover, the machining process is reduced, the machining cost is reduced, and the practical application value is higher.

Embodiments described herein relate to electrochemical cells with multiple separators, and methods of producing the same. A method of producing an electrochemical cell can include disposing an anode material onto an anode current collector, disposing a first separator on the anode material, disposing a cathode material onto a cathode current collector, disposing a second separator onto the cathode material, and disposing the first separator on the second separator to form the electrochemical cell. The anode material and / or the cathode material can be a semi-solid electrode material including an active material, a conductive material, and a volume of liquid electrolyte. In some embodiments, less than about 10% by volume of the liquid electrolyte evaporates during the forming of the electrochemical cell. In some embodiments, the method can further include wetting the first separator and / or the second separator with an electrolyte solution prior to coupling the first separator to the second separator.

A secondary battery and an electric device. In the secondary battery, solvents with a high viscosity and a low viscosity are combined, specific types of electrolyte additives are compounded and build a parameter relationship together with the resistivity of a negative electrode film, and therefore the overall electrolyte injection amount is increased without affecting the electron conduction of a negative electrode, thereby improving the infiltration effect of an electrolyte; moreover, since unique electrolyte components are selected, the degree of interfacial side reactions of the electrolyte is low during operation of the secondary battery, the probability of gas production is low at a normal temperature or high temperature, and the ion conduction capability is high. The secondary battery has good dynamic performance, low risks of high-temperature gas production and a DCR increase, and ideal fast-charge application performance.

Embodiments described herein relate to electrochemical cells with multiple separators, and methods of producing the same. A method of producing an electrochemical cell can include disposing an anode material onto an anode current collector, disposing a first separator on the anode material, disposing a cathode material onto a cathode current collector, disposing a second separator onto the cathode material, and disposing the first separator on the second separator to form the electrochemical cell. The anode material and / or the cathode material can be a semi-solid electrode material including an active material, a conductive material, and a volume of liquid electrolyte. In some embodiments, less than about 10% by volume of the liquid electrolyte evaporates during the forming of the electrochemical cell. In some embodiments, the method can further include wetting the first separator and / or the second separator with an electrolyte solution prior to coupling the first separator to the second separator.

Disclosed herein are halide-based solid electrolytes with high ionic conductivity for all-solid-state sodium ion batteries. For example, disclosed herein are solid electrolytes comprising: ABCλ-2x-zDx+y, wherein: A is chosen from Li, Na, K, Mg, Ca, Zn, Al, In, Fe, and combinations thereof; B is chosen from Ca, Mg, Zn, In, V, Nb, Ta, Mn, Ti, Zr, Hf, Fe, Co, Ni, Al, Ga, and combinations thereof; C is chosen from F, Cl, Br, I, and combinations thereof; D is chosen from O, S, Se, Te, and combinations thereof; λ is an integer chosen from 4, 5, and 6, such that the solid electrolyte is charge neutral; 0 < x < 1; 0 < z < 2; and 0 < y < 1.

The invention discloses a solid electrolyte with high ionic conductivity, which comprises the following components: a matrix material: a halide super ion conductor with a LiMXCl4 structure, M being selected from at least one of Ta, Nb and Hf, X being O or F, a chemical general formula being LiM1-aX1-6Cl4, a being equal to 0.1-0.3, and an electrochemical window being regulated to 2.5-4.0 V through fluorine-chlorine mixed anion substitution; the second phase material is a core-shell structure compound, the core is Li3TiCl6, and the shell is a Li3PS4 interface layer; and the sintering aid is a compound of Li3BO3 and LiF. Through fluorine-chlorine mixed anion regulation and control and MO2Cl4 octahedron synergistic tilting mechanism, the ionic conductivity of the solid electrolyte is remarkably improved, the lithium ion conductivity at room temperature is greater than or equal to 10mS / cm, the activation energy is less than or equal to 0.2 eV and is superior to that of the traditional halide electrolyte, and meanwhile, the free volume between chains is optimized through Zr < 4 + > / Sn < 2 + > gradient doping, so that the performance of the solid electrolyte is improved. The core-shell structure compound and the silane coupling agent are combined for modification, so that the electrochemical window is effectively widened to 2.5-4.0 V, the interface side reaction is inhibited, and the composite material is adaptive to a high-voltage positive electrode material.

The invention provides a battery monomer, a battery device and electric equipment, the battery monomer comprises an electrode assembly and an electrolyte, the electrode assembly comprises a positive pole piece, the positive pole piece comprises a positive current collector and a positive active material layer arranged on at least one side of the positive current collector, and the positive active material layer is arranged on the positive current collector. The size of the positive electrode active material layer along the length direction of the battery monomer is 300mm-950mm; the electrolyte comprises a lithium salt, and based on the total mass of the electrolyte, the mass ratio of the lithium salt is 10%-18%; the lithium salt comprises fluorine-containing sulfimide lithium salt and lithium hexafluorophosphate, based on the total mass of the electrolyte, the ratio of the mass ratio of the fluorine-containing sulfimide lithium salt to the mass ratio of the lithium hexafluorophosphate is 0.4-1, and the viscosity of the electrolyte at normal temperature is 2.3 mPa.s-3. 5 mPa.s.

A method for producing a pyrochlore-type oxide including, in the composition, a plurality of cations including an alkali metal cation, the method comprising: a mixing step (S10, S20) for mixing a plurality of raw materials each containing a plurality of cations; and a heating step (S11, S21) for heating the mixture containing the plurality of raw materials at a prescribed temperature by using a liquid phase method to generate a composite oxide including, in the composition, at least an alkali metal cation and having a corundum structure.

The invention discloses an oxyhalide solid electrolyte, a preparation method thereof and an all-solid-state battery, and relates to the technical field of batteries. The solid electrolyte is LiaMbNcXdOe, M and N are the same elements or different elements, and M and N are at least one of Zn, Ba, Al, In, Y, Cr, Ti, Zr, Hf, Nb, Ta, La, Ce, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu; x is at least one of F, Cl, Br and I. The oxyhalide solid electrolyte with high ionic conductivity and cost advantage is prepared by selecting high-valence metal oxide, halide and lithium halide through a ball milling method and combining annealing and hot pressing processes, and the oxyhalide solid electrolyte can show good electrochemical performance when being applied to all-solid-state lithium metal batteries.

The invention provides a non-aqueous electrolyte which comprises a first sodium salt, a second sodium salt and a third sodium salt, the first sodium salt comprises at least one of sodium hexafluorophosphate, sodium hexafluoroarsenate, sodium perchlorate and sodium trifluoroacetate; the second sodium salt comprises one, two or more of sodium salt with sulfonate radical, sodium salt with oxalate radical, sodium salt with phosphate radical and sodium salt with borate radical. The non-aqueous electrolyte provided by the invention is suitable for the sodium-ion battery, can improve the normal-temperature and high-temperature cycle performance of the sodium-ion battery and the capacity retention rate after high-temperature storage, and can significantly reduce the volume expansion rate of the sodium-ion battery after high-temperature storage.

The invention discloses a battery monomer, a battery device and electric equipment, the battery monomer comprises an electrode assembly and an electrolyte, the electrode assembly comprises a positive pole piece, the positive pole piece comprises a positive current collector and a positive active material layer arranged on at least one side of the positive current collector, and the positive active material layer comprises lithium-containing phosphate; the electrolyte comprises a carboxylic ester solvent and a linear carbonic ester solvent, based on the total mass of the electrolyte, the mass ratio of the carboxylic ester solvent is 5%-25%, and the mass ratio of the linear carbonic ester solvent is 20%-49%; the electrolyte further comprises a non-lithium salt additive, the non-lithium salt additive comprises a phosphate ester additive, and the non-lithium salt additive further comprises at least one of a carbonate ester additive, a sulfate ester additive, a borate ester additive, a silane additive and a sultone additive. The total mass of the non-lithium salt additive accounts for 0.1%-5%.

The invention discloses a battery monomer, a battery device and a power utilization device. The battery monomer comprises an electrode assembly and an electrolyte; wherein the electrode assembly comprises a positive electrode plate and a negative electrode plate, a positive electrode film layer of the positive electrode plate comprises a positive electrode active material, the positive electrode active material comprises lithium-containing phosphate, and the porosity of the positive electrode plate is 20-30%; a negative electrode film layer of the negative electrode plate comprises a negative electrode active material, the negative electrode active material comprises graphite, and the porosity of the negative electrode plate is 24-33%; the electrolyte comprises an electrolyte salt and a solvent, the solvent comprises chain carboxylic ester and chain carbonic ester, the mass ratio of the chain carboxylic ester in the electrolyte is 8.5%-40%, and the mass ratio of the chain carbonic ester in the electrolyte is 8.5%-50%. According to the technical scheme, good fast charging performance, good cycle performance and high energy density of the battery are considered.

The invention provides a battery monomer, a battery device and electric equipment, the battery monomer comprises an electrode assembly and an electrolyte, the electrode assembly comprises a positive pole piece and a negative pole piece, the positive pole piece comprises a positive current collector and a positive active material layer arranged on at least one side of the positive current collector, and the positive active material layer comprises a positive active material; the positive electrode active material comprises lithium-containing phosphate, and the compaction density of the positive electrode plate is 2.46 g / cm < 3 >-2.8 g / cm < 3 >; the negative pole piece comprises a negative current collector and a negative active material layer arranged on at least one side of the negative current collector, and the compaction density of the negative pole piece is 1.25 g / cm < 3 >-1.5 g / cm < 3 >; the electrolyte comprises fluorine-containing lithium sulfimide and lithium hexafluorophosphate, and based on the total mass of the electrolyte, the ratio of the mass ratio of the fluorine-containing lithium sulfimide to the mass ratio of the lithium hexafluorophosphate is 0.4-0.8; and the mass of the electrolyte corresponding to each Ah of the battery monomer is 2.2-3g.

Embodiments described herein relate to electrochemical cells with multiple separators, and methods of producing the same. A method of producing an electrochemical cell can include disposing an anode material onto an anode current collector, disposing a first separator on the anode material, disposing a cathode material onto a cathode current collector, disposing a second separator onto the cathode material, and disposing the first separator on the second separator to form the electrochemical cell. The anode material and / or the cathode material can be a semi-solid electrode material including an active material, a conductive material, and a volume of liquid electrolyte. In some embodiments, less than about 10% by volume of the liquid electrolyte evaporates during the forming of the electrochemical cell. In some embodiments, the method can further include wetting the first separator and / or the second separator with an electrolyte solution prior to coupling the first separator to the second separator.

The invention discloses an electrolyte for a lithium manganate lithium ion battery and a preparation method thereof, and the electrolyte comprises the following components in percentage by mass: 70-90% of an organic solvent, 5-20% of a lithium salt and 0.5-10% of an additive, the organic solvent is formed by mixing cyclic carbonate and chain carbonate according to the mass ratio of (10-30): (70-90); the lithium salt adopts one or more of lithium hexafluorophosphate (LiPF), lithium tetrafluoroborate (LiBF) and lithium bis (trifluoromethane sulfonimide) (LiTFSI), and the concentration of the lithium salt is 0.8 to 1.5 mol / L; the additives comprise a manganese ion complexing agent, a film forming accelerant and an antioxidant. In the invention, the manganese ion inhibition effect is as follows: the complexing agent and Mn (II) ions form a stable complex, so that the concentration of free Mn (II) in the electrolyte is reduced by more than 80%, migration and deposition of the free Mn (II) to the negative electrode are inhibited, and the dissolution amount of the Mn element of the positive electrode is reduced by 65% after 500 times of circulation at 45 DEG C.

The invention relates to the technical field of batteries, in particular to a composite solid electrolyte material as well as a preparation method and application thereof. A composite solid electrolyte material comprises a base material and a composite coating layer located on the surface of the base material, the composite coating layer comprises a first coating layer and a second coating layer, the first coating layer is located on the surface of the base material, and the second coating layer is located on the surface of the first coating layer; the matrix material comprises a sulfide electrolyte material; the first coating layer is prepared from Li3PS4 and LiCl; the second coating layer contains LiF and LiPO4. According to the composite solid electrolyte material disclosed by the invention, the first coating layer (Li3PS4 and LiCl) and the second coating layer (Li3PS4 and LiCl) are arranged on the surface of the base material and are coordinated and matched, so that the composite solid electrolyte material has high ionic conductivity and high chemical and electrochemical stability.

The invention provides an oxide solid electrolyte material and a preparation method and application thereof, and relates to the technical field of electrolyte material preparation, the preparation method comprises the following steps: 1) preparing pure-phase lithium borate from BLiO2, Li2O and B4Li2O7 according to a certain proportion under a certain condition; 2) mixing lithium borate with a zirconium source, a lithium source and a doping agent according to a certain proportion, and carrying out ball milling or wet ball milling / drying; 3) then tabletting, carrying out primary high-temperature solid-phase sintering, crushing and the like; and 4) finally, mixing and ball-milling the doped and modified LZBO and a coating agent, tabletting, and then carrying out secondary high-temperature solid-phase sintering, crushing and the like to obtain the LZBO material. Aiming at the defects of the traditional high-temperature solid-phase synthesis method, by innovating raw material combination and process steps, the reaction temperature is reduced, the product purity and the production efficiency are improved, and energy conservation and emission reduction are realized. According to the invention, the ionic conductivity, the compaction density, the battery rate, the cycle performance and the like are improved, and the application range is widened.

A solid electrode includes particles of an electroactive material, a solid electrolyte comprising particles of an ionic conducting compound having at least one halogen element, a conductive carbon, and a coating deposited on the particles of the electroactive material, the particles of the solid electrolyte, or a combination thereof. The coating includes a metal halide, a metal sulfide, a metal phosphide, a metal oxide, a metal selenide, or a combination of two or more thereof. A method for preparing the solid electrode includes milling a mixture of the electroactive material, the conductive carbon, and the solid electrolyte to produce the coated solid electrode material comprising the coating derived from decomposition products of the ionic conducting compound, the coating deposited on the particles of the electroactive material, the solid electrolyte, or a combination thereof.

The present invention discloses a preparation method and application of a sulfide solid electrolyte material. The electrolyte has a Li6PS5Cl-type structure, and its chemical general formula is Li6Nb 1‑a P a S5X(0

The invention provides an electrolyte and a silicon-based lithium ion battery. The electrolyte comprises a lithium salt, an organic solvent and an additive, the mass ratio of the additive in the electrolyte is 0.1%-10%, and the additive comprises a sulfur-containing compound and a silazane compound. The sulfur-containing compound has stronger electrochemical reduction tendency and can be preferentially reduced to generate an SEI film, meanwhile, the formed SEI comprises Li2SO3, CH3CH (OSO2Li) and the like, and the components can improve the stability of the SEI film and inhibit the volume expansion of the silicon negative electrode. The silazane compound can form a protective film containing a silicon-nitrogen bond on the surface of the negative electrode, so that the thermal stability and the electrochemical stability of the electrolyte are improved. According to the electrolyte formula disclosed by the invention, the problem of poor cycling stability of the silicon-based lithium ion battery is effectively solved by controlling the types and the concentrations of the additives and utilizing the synergistic effect, and the first effect of the silicon-based lithium ion battery is also improved.

The invention provides a single battery, a battery device and a power utilization device, the single battery comprises an electrode assembly, the total width of a positive pole lug part accounts for 50%-100% of the total size of a pole lug connecting edge along the extension direction of the pole lug connecting edge of a positive pole main body part, and the total width of a negative pole lug part accounts for 50%-100% of the total size of the pole lug connecting edge along the extension direction of the pole lug connecting edge of a negative pole main body part; wherein the coating weight of the single negative electrode active material layer is 0.1 g / 1540.25 mm < 2 >-0.145 g / 1540.25 mm < 2 >, the electrolyte comprises at least one of dimethyl carbonate and linear carboxylic ester, the structural formula of the linear carboxylic ester meets R1-COO-R2, and R1 and R2 are independently selected from C1-C5 alkyl or halogenated alkyl respectively; based on the total mass of the organic solvent, the mass fraction of the first solvent is 4-72%.

The invention relates to the technical field of electrochemistry, and provides a sulfide solid electrolyte, a preparation method thereof, a battery and application. The chemical formula of the sulfide solid electrolyte is Li7-aPS6-aXa, X is halogen, and a is greater than or equal to 1 and less than or equal to 2; wherein the peak area of a diffraction peak corresponding to a (111) crystal plane of the sulfide solid electrolyte is I1, the peak area of a diffraction peak corresponding to a (311) crystal plane of the sulfide solid electrolyte is I2, and I1 / I2 is larger than or equal to 0.2 and smaller than or equal to 0.3. The I1 / I2 of the sulfide solid electrolyte disclosed by the invention is within the range, a good crystal structure and a relatively large interface area can be provided, and ion movement is promoted, so that relatively high ionic conductivity is obtained. Furthermore, according to the method disclosed by the invention, the high ionic conductivity of the product is ensured by reducing the solvent dosage and optimizing the sintering step, and meanwhile, the environmental pollution, the energy consumption and the production cost are remarkably reduced.

The present invention discloses a non-aqueous electrolyte for a secondary battery and a secondary battery thereof, the electrolyte comprises an electrolyte salt, a non-aqueous solvent and an additive, the additive at least comprises: a nitrogen-containing heterocyclic compound as a first additive, a film-forming additive with a film-forming potential of less than 1.5 V (vs. Li + / Li) as a second additive, the specific structure of the additive is shown in the specification. The nitrogen-containing heterocyclic compound and the film-forming additive with the film-forming potential lower than 1.5 V (vs.Li < + > / Li) are combined for use, and the nitrogen-containing heterocyclic compound and the film-forming additive are regulated in a specific content ratio range to fully generate a synergistic effect, so that water catching and acid inhibition can be effectively realized, decomposition and gas production can be effectively inhibited at high temperature and high voltage, the stability of the electrolyte is greatly improved, and the service life of the electrolyte is prolonged. And an SEI film with excellent ion transmission capability and structure / thermal stability can be formed on the surface of the electrode, so that the first efficiency of the battery is effectively improved, and the low-temperature performance and the cycle performance of the battery are further improved.

The invention provides a battery monomer, a battery device and a power utilization device. In the battery monomer, a positive active material comprises lithium-containing phosphate with an olivine structure, and in a cross section of a positive film layer along a thickness direction, the lithium-containing phosphate with the olivine structure comprises first lithium-containing phosphate particles with a longest diameter of 0.05-0.3 [mu] m and second lithium-containing phosphate particles with a longest diameter of 1-3 [mu] m; the average particle diameter Dv50 of the negative electrode active material is 8 [mu] m to 15 [mu] m, and the negative electrode active material includes graphite.