CN106558692A - A kind of lithium battery negative pole and its preparation and application - Google Patents

Abstract

The invention discloses a kind of lithium battery new negative pole and its preparation method and application, belongs to field of chemical power source.The new negative pole is composited by the negative material without lithium of layer of metal lithium and a floor height specific capacity.By this new negative pole and the composition secondary cell of the positive electrode without lithium, the practical application of the height ratio capacity positive electrode without lithium source is capable of achieving.While battery discharge, in negative pole in-situ preparation lithium alloy.The Li dendrite being likely to result in when can also be solved the problems, such as individually using lithium metal as negative pole using this new negative pole, and the thus cyclical stability difference and safety problem of caused battery.The preparation method is simple of this new negative pole disclosed by the invention, prepares secondary cell using this new negative pole, can simplify cell making process, reduces electrode material and prepares and battery cost of manufacture.

Description

A kind of negative electrode for lithium battery and its preparation and application

technical field

The invention relates to a negative electrode of a secondary battery, in particular to a novel negative electrode of a lithium battery and a preparation method and application thereof. It belongs to the field of chemical power supply.

Background technique

Carbon materials such as graphite are widely used as negative electrodes in currently marketed lithium secondary batteries. Although graphite is safer than metal lithium, its theoretical specific capacity is only 372mAh/g. Therefore, the development of high-capacity, high-safety anode materials has received widespread attention and has become one of the effective means to improve battery performance. For example, the theoretical specific capacity of silicon is as high as 4200mAh/g, which is the highest value among the elements that can be alloyed with lithium at present. Its actual specific capacity is 10 times that of graphite. At the same time, silicon is not easy to deposit metal lithium during charging, so it is safer than graphite. The theoretical specific capacity of aluminum is 2234mAh/g, about 7 times that of graphite negative electrode. The theoretical specific capacity of tin is also 990mAh/g. Therefore, this type of anode material that can be alloyed with lithium has broad development prospects. In addition, metal oxides can also be used as negative electrode materials because they can undergo redox reactions with lithium to achieve charge and discharge. This kind of metal oxide has high theoretical specific capacity, for example: MnO ₂ is 1232mAh/g, Fe ₂ O ₃ is 1007mAh/g, NiO is 718mAh/g, CoO is 715mAh/g, etc.

At the same time, most of the existing cathode materials with high theoretical specific capacity do not contain elemental lithium, including metal oxides and sulfur. When using a negative electrode with a lower voltage platform, the metal oxide can be used as the positive electrode. For example, the discharge potential of TiO ₂ is about 1.7V (vs. Li/Li ⁺ ), which can form a battery with a lower silicon-based negative electrode (0-0.1V). In addition, the theoretical specific capacity of elemental sulfur in lithium-sulfur battery system, which is currently a research hotspot, is as high as 1675mA/g. The application of this high specific capacity cathode material is of great significance for improving the energy density of secondary batteries.

In order to form a battery matched with a cathode material without a lithium source, lithium must be provided at the anode. If lithium or lithium alloys are directly used as the negative electrode, the production, transportation, and battery assembly of the negative electrode materials need to be carried out in a protective atmosphere and dry environment, which increases the cost and process difficulty of the battery. Moreover, lithium alloys in powder form or strip form have relatively high hardness, and it is easy to pierce the diaphragm when making batteries, causing battery short circuits, or making electrodes difficult, so it is difficult to apply to lithium battery negative electrodes. Therefore, there is an urgent need to develop new negative electrode materials and their preparation methods to reduce the cost and difficulty of battery production while maintaining high capacity density and energy density of the battery.

Contents of the invention

The object of the present invention is to provide a novel negative electrode for a lithium battery and its preparation method and application. This new type of negative electrode can not only realize the application of lithium-free positive electrode materials with high specific capacity, but also avoid the dendrite problem that may be caused by using metallic lithium negative electrodes alone, and at the same time realize the in-situ generation of lithium alloys at the negative electrode. The preparation method has the characteristics of simplified process, reduced cost and the like.

The content of the present invention includes: the novel negative electrode is composed of metal lithium and a lithium-free negative electrode material with a high specific capacity, and has a two-layer structure, one layer is metal lithium, and the other is a high specific capacity lithium-free material. Negative material layer. A secondary battery is formed with a lithium-free positive electrode material.

The electrode structure of the negative electrode is a two-layer laminated structure, which is composed of a metal lithium layer and a lithium-free negative electrode material with a high specific capacity; one layer is metal lithium, and the other is a high specific capacity lithium-free material. Negative electrode material layers, they are closely attached.

The lithium-free negative electrode material with high specific capacity is silicon, metal tin, metal aluminum, metal antimony, tin oxide, iron oxide, nickel oxide, cobalt oxide, copper oxide, molybdenum oxide, titanium One or more of oxides, vanadium oxides, tungsten oxides, niobium oxides, and cerium oxides.

First, a high specific capacity lithium-free negative electrode material layer is prepared on the surface of the current collector, and then a metal lithium layer is prepared on the surface of the high specific capacity lithium free negative electrode material layer away from the current collector.

The material used as the negative electrode collector can be copper, nickel, iron or stainless steel; the shape can be mesh or sheet.

The method used to prepare a high specific capacity lithium-free negative electrode material layer on the surface of the current collector is one or more of electrochemical methods, coating methods, thermal evaporation methods, magnetron sputtering methods or ion beam sputtering methods ;

The method for preparing the metal lithium layer in the negative electrode may be one or more of mechanical rolling, sputtering coating, ion coating or vacuum evaporation.

The mass ratio of metal lithium to lithium-free negative electrode material in the negative electrode is 1:10-11:10.

The negative electrode and the positive electrode without lithium source form a secondary battery, and there is a separator between the negative electrode and the positive electrode, which only allows lithium ions to pass through, and an electrolyte.

The positive electrode material without lithium source can be metal oxide or elemental sulfur;

The metal oxide cathode material is an oxide containing one or more than two metal elements in Sn, Co, Fe, Ni, Cu, Mo, Mn, Ti, V, W, Nb, Ce;

The elemental sulfur is one or more of refined sulfur, sublimed sulfur or precipitated sulfur.

The preparation process of the positive electrode without a lithium source is to prepare a positive electrode without a lithium source on the surface of the current collector by electrochemical methods, coating, thermal evaporation, magnetron sputtering or ion beam sputtering to form a pole piece;

The material used as the positive electrode collector can be aluminum, copper, nickel, iron or stainless steel, and the shape can be mesh or sheet.

The diaphragm material can be a high molecular polymer or an inorganic compound;

The high molecular polymer is polyethylene, polypropylene, polyvinylidene fluoride-hexafluoropropylene, polyacrylonitrile, polymethyl methacrylate, polyvinyl chloride, polyethylene oxide, or a composite of two or more thing;

The inorganic compound is Li _3x La _2/3-x TiO ₃ (0.04<x<0.17) or Li ₁₄ ZnGe ₄ O ₁₆ or Li _1+x A _{2- x} B _x (PO ₄ ) ₃ (A=Ti, Ge, B=Al, Ga, Sc, In, Y, 0≤x≤0.7) or Li _5+x La _3-x A _x M ₂ O ₁₂ (A=Ba, Sr, M=Zr, Ta, Nb, Sb,Bi,0≤x≤2) or xLi ₂ S-(1-x)P ₂ S ₅ (0<x<1) or xLi ₂ S-(1-x)SiS ₂ (0<x<1) or Li ₁₀ GeP ₂ S ₁₂ or Li ₄ GeS or Li ₃ Zn _0.5 GeS ₄ or Li _3.25 Ge _0.25 P _0.75 S ₄ or Li _3.4 Si _0.4 P _0.6 S ₄ or Li _4.8 Si _0.2 Al _0.8 S ₄ or Li ₆ PS ₅ X (X=Cl, Br or I) or one or more complexes of lithium nitrogen phosphate.

The electrolyte can be an organic electrolyte, a gel electrolyte or a solid electrolyte;

The electrolyte is composed of a solvent and a lithium salt; the solvent is ethylene glycol dimethyl ether, 1-dioxolane, tetrahydrofuran, diglyme, tetraglyme, o-xylene, ethylene carbonate , dimethyl carbonate, ethyl methyl carbonate or one or more mixed solvents; lithium salts are lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, lithium trifluoromethanesulfonate 1. One or more mixed lithium salts of lithium bistrifluoromethanesulfonylimide;

The gel electrolyte is composed of a polymer and an organic electrolyte; wherein, the polymer can be one of polyvinylidene fluoride-hexafluoropropylene, polyacrylonitrile, polymethyl methacrylate, polyvinyl chloride, and polyethylene oxide. or a mixture of two or more; the solvent of the organic electrolyte can be ethylene glycol dimethyl ether, 1-dioxolane, tetrahydrofuran, diglyme, tetraethylene glycol dimethyl ether, o-xylene, carbonic acid One or more mixed solvents of vinyl ester, dimethyl carbonate, and ethyl methyl carbonate; the lithium salt of the organic electrolyte can be lithium hexafluorophosphate, lithium tetrafluoroborate, lithium hexafluoroarsenate, lithium perchlorate, One or more mixed lithium salts of lithium trifluoromethanesulfonate and lithium bistrifluoromethanesulfonylimide;

The solid electrolyte is xLi ₂ S-(1-x)P ₂ S ₅ (0<x<1), xLi ₂ S-(1-x)SiS ₂ (0<x<1), Li ₁₀ GeP ₂ S _12. Li ₄ GeS ₄ , Li ₃ Zn _0.5 GeS ₄ , Li _3.25 Ge _0.25 P _0.75 S ₄ , Li _3.4 Si _0.4 P _0.6 S ₄ , Li _4.8 Si _0.2 Al _0.8 S ₄ , Li ₆ PS ₅ X (X=Cl ,Br,I), Li _3x La _2/3-x TiO ₃ (0.04<x<0.17), Li ₁₄ ZnGe ₄ O ₁₆ , Li _1+x A _2-x B _x (PO ₄ ) ₃ (A=Ti ,Ge,B=Al,Ga,Sc,In,Y,0≤x≤0.7), Li _5+x La _3-x A _x M ₂ O ₁₂ (A=Ba,Sr,M=Zr,Ta,Nb , Sb or Bi, 0≤x≤2), one or more complexes of lithium nitrogen phosphate.

The advantages of the present invention:

Compared with the prior art, the advantages of the new lithium battery negative electrode and its preparation method proposed by the present invention are: the negative electrode has a simple layered structure, and the preparation process is simple. When an alloyable negative electrode material is used, a lithium alloy can be formed in situ at the negative electrode through the first discharge and charge reaction, which simplifies the manufacturing process of the battery and reduces the cost and difficulty of making the battery. In particular, lithium alloys with nanoscale structures and their negative electrodes can be obtained relatively easily by preparing nanoscale metal or alloy (composite) materials, and then undergoing the first discharge and charge reactions of the battery. However, it is quite difficult to prepare nanoscale lithium alloy powder materials and their pole pieces by conventional methods. And, after the first discharge, the metal lithium in the battery dissolves in the electrolyte to generate Li ⁺ , and Li ⁺ reacts with the metal (alloy) in the negative electrode to form a lithium alloy in the subsequent discharge reaction; compared with batteries using metal lithium negative electrodes , the use of the negative electrode of the present invention also improves the safety of the battery. In addition, the new negative electrode is suitable for positive electrode materials with high specific capacity, and can be applied in lithium-ion batteries and lithium-sulfur batteries. In summary, the promotion and application of this new type of negative electrode has broad prospects.

Description of drawings

Fig. 1 is a schematic structural view and working principle of a secondary battery using the novel negative electrode of the present invention.

working principle:

First discharge: negative electrode: Li→Li ⁺ +e ^-

Positive electrode: positive electrode without lithium source + Li ⁺ + e ^- → positive electrode with lithium source

First charge: negative electrode: negative electrode without lithium source + Li ⁺ + e ^- → negative electrode with lithium source

Positive electrode: positive electrode containing lithium source → positive electrode without lithium source +Li ⁺ +e ^-

detailed description

Example 1

1 g of precipitated sulfur was used as the positive electrode, and the sulfur positive electrode was prepared on the surface of the aluminum foil current collector by coating. A layer of about 0.4 g of elemental silicon was prepared by coating on the surface of a copper foil current collector with an area of about 17 cm ² on one side. A layer of metal lithium with a mass of about 0.43 g is mechanically pressed on the surface of elemental silicon to make a negative electrode. Assemble the sulfur positive electrode, porous polypropylene diaphragm, and silicon-metal lithium composite negative electrode into a battery, and inject lithium bistrifluoromethanesulfonic acid imide (LiTFSI) at a concentration of 1mol/L as lithium salt, diethylene glycol dimethyl Ether (DME) + 1,3-dioxolane (DOL) (volume ratio 1:1) is the electrolyte solution of the solvent.

The battery is discharged at a constant current with a current density of 80mA/g, and the lower limit of the discharge voltage is 1.5V. This process is to lithiate the sulfur positive electrode, and the metal lithium in the negative electrode is consumed. The specific capacity of the battery for the first discharge is about 1231mAh/g. After the battery is recharged thereafter, the positive electrode is sulfur and the negative electrode is a lithium-silicon alloy.

Example 2

About 0.5 g of Fe ₂ O ₃ positive electrode was prepared on the surface of nickel foam current collector by electrochemical deposition. A layer of about 0.23g aluminum film was prepared by thermal evaporation on the surface of a stainless steel sheet current collector with an area of about 50cm2 ^on one side. A layer of lithium metal of about 0.13 is evaporated on the aluminum surface. Fe ₂ O ₃ positive electrode, polyvinylidene fluoride-hexafluoropropylene diaphragm, metal aluminum-lithium composite negative electrode, 1mol/L lithium hexafluorophosphorus (LiPF ₆ ) lithium salt, ethylene carbonate (EC) + diethyl carbonate (DEC) (volume ratio 1:1) as a solvent electrolyte, assembled into a lithium secondary battery.

The battery is discharged at a constant current with a current density of 100mA/g, and the lower limit of the discharge voltage is 0.01V. This process is to reduce the Fe ₂ O ₃ positive electrode, and the metal lithium in the negative electrode is consumed. The specific capacity of the battery for the first discharge is about 1163mAh/ g. After the battery is recharged, the positive electrode is Fe ₂ O ₃ , and the negative electrode is lithium aluminum alloy.

Example 3

A positive electrode of about 2g of TiO ₂ was prepared on the copper foil current collector by magnetron sputtering, and a layer of about 0.43g of SnO ₂ was prepared on the surface of the copper mesh current collector with an area of about 15cm ² on one side by electrochemical deposition. A layer of about 0.087 g of metallic lithium was sputtered on the surface of _SnO2 . The TiO ₂ positive pole, the SnO ₂ -metal lithium composite negative pole, and the Li ₇ LaZr ₂ O ₁₂ solid electrolyte are assembled into a lithium secondary battery.

The battery is discharged with a constant current at a current density of 2mA/g, and the lower limit of the discharge voltage is 0.01V. This process is to perform lithium intercalation treatment on the positive electrode of TiO ₂ , and the metal lithium in the negative electrode is consumed. The specific capacity of the battery for the first discharge is about 120mAh/g.

Example 4

A layer of 1 g CuO cathode was prepared on the stainless steel current collector by magnetron sputtering. A layer of about 0.16 g of elemental silicon was prepared by coating on the surface of a copper foil current collector with an area of about 13 cm ² on one side. A layer of about 0.175g of metallic lithium is hot-pressed on the silicon surface. CuO positive electrode, silicon-metal lithium composite negative electrode, polyacrylonitrile diaphragm, lithium perchlorate (LiClO ₄ ) lithium salt with a concentration of 1mol/L, ethylene carbonate (EC) + dimethyl carbonate (DMC) + carbonic acid Ethyl methyl ester (EMC) (volume ratio 1:1:1) is used as the electrolyte solution of the solvent, and the lithium secondary battery is assembled.

The battery is discharged at a constant current with a current density of 60mA/g, and the lower limit of the discharge voltage is 0.01V. This process is to reduce the CuO positive electrode, and the metal lithium in the negative electrode is consumed. The specific capacity of the battery for the first discharge is about 616mAh/g. Thereafter the battery is recharged with CuO as the positive electrode and lithium-silicon alloy as the negative electrode.

Example 5

About 0.5 g of refined sulfur positive electrode was prepared on the surface of aluminum foil current collector by coating method. A layer of about 0.85g of metallic tin was prepared by thermal evaporation on the surface of a copper mesh current collector with an area of about 40cm ^on one side. A layer of metal lithium with a mass of about 0.22 g is vapor-deposited on the surface of the tin to make a negative electrode. A lithium secondary battery is assembled with a sulfur positive electrode, a Li ₁₀ GeP ₂ S ₁₂ solid electrolyte, and a metal tin-lithium composite negative electrode.

The battery is discharged at a constant current with a current density of 10mA/g, and the lower limit of the discharge voltage is 1.5V. This process is to lithiate the sulfur positive electrode, and the metal lithium in the negative electrode is consumed. The specific capacity of the battery for the first discharge is about 1160mAh/g. Thereafter the battery is recharged with sulfur as the positive electrode and lithium-tin alloy as the negative electrode.

Example 6

About 2.1 g of CoFe ₂ O ₄ positive electrode was prepared on the surface of stainless steel sheet current collector by electrochemical deposition. A layer of about 0.86 g of metallic aluminum was prepared by thermal evaporation on the surface of a stainless steel sheet current collector with an area of about 60 cm ² on one side. A layer of about 0.5 g of metallic lithium is vapor-deposited on the aluminum surface. CoFe ₂ O ₄ positive electrode, polyacrylonitrile-based methyl acrylate polymer diaphragm, metal aluminum-lithium composite negative electrode, lithium tetrafluoroborate (LiBF ₄ ) lithium salt at a concentration of 1mol/L, ethylene carbonate (EC)+ Dimethyl carbonate (DMC) (volume ratio 1:1) is used as the electrolyte solution of the solvent, and the lithium secondary battery is assembled.

The battery is discharged at a constant current with a current density of 200mA/g, and the lower limit of the discharge voltage is 0.01V. This process is to reduce the CoFe ₂ O ₄ positive electrode, and the metal lithium in the negative electrode is consumed. The specific capacity of the battery for the first discharge is about 890mAh/g . Thereafter the battery is recharged, the positive electrode is CoFe ₂ O ₄ , and the negative electrode is lithium aluminum alloy.

Example 7

About 1.5 g of sedimented sulfur cathode was prepared on the surface of aluminum foil current collector by coating method. A silicon electrode of about 0.6 g was prepared by a coating method on the surface of a copper foil current collector with an area of about 50 cm ² on one side. A layer of lithium metal with a mass of about 0.65 g is mechanically pressed on the silicon surface to make a negative electrode. Sulfur positive electrode, ethylene oxide diaphragm, silicon-metal lithium composite negative electrode, 1mol/L lithium bistrifluoromethanesulfonate imide (LiTFSI) as lithium salt, diethylene glycol dimethyl ether (DME) +1, 3-dioxolane (DOL) (volume ratio 1:1) is used as the electrolyte solution of the solvent, and the lithium secondary battery is assembled.

The battery is discharged at a constant current with a current density of 160mA/g, and the lower limit of the discharge voltage is 1.5V. This process is to lithiate the sulfur positive electrode, and the metal lithium in the negative electrode is consumed. The specific capacity of the battery for the first discharge is about 1096mAh/g. The battery is then recharged with sulfur as the positive electrode and lithium-silicon alloy as the negative electrode.

Comparative example 1

About 1.5 g of sedimented sulfur cathode was prepared on the surface of aluminum foil current collector by coating method. A lithium-silicon alloy electrode with an area of about 50 cm ² and a mass of about 1.25 g was prepared by mechanical lamination on the surface of the copper foil current collector. Sulfur positive electrode, ethylene oxide diaphragm, lithium-silicon alloy negative electrode, 1mol/L lithium bistrifluoromethanesulfonate imide (LiTFSI) as lithium salt, diethylene glycol dimethyl ether (DME) + 1,3- Dioxolane (DOL) (volume ratio 1:1) is used as the electrolyte solution of the solvent, and the lithium secondary battery is assembled.

The battery is discharged at a constant current with a current density of 160mA/g, and the lower limit of the discharge voltage is 1.5V. This process is to lithiate the sulfur positive electrode, and the metal lithium in the negative electrode is consumed. The specific capacity of the battery for the first discharge is about 761mAh/g.

It can be seen from the above experiments that the present invention provides a safe lithium battery negative electrode. Using this new type of high-capacity negative electrode, after 20 battery charge and discharge cycles, the capacity of the lithium-sulfur battery remains above 800mAh/g, and the capacity of the lithium-ion battery can reach above 90mAh/g (TiO ₂ is used as the positive electrode) or higher. As a comparative example, the lithium-sulfur battery using lithium-silicon alloy powder as the negative electrode has a capacity of only 510mAh/g after 20 charge-discharge cycles under the same conditions. It can be seen that the novel negative electrode disclosed in the present invention is not only conducive to improving the safety of the battery, but also provides a battery system with high energy density.

Although the content of the present invention is specifically introduced through the above-mentioned embodiments, the above-mentioned embodiments should not be regarded as limiting the present invention. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (10)

1. a kind of lithium battery negative pole, it is characterised in that：The electrode structure of the negative pole is two-layer laminate structure, by metallic lithium layer and is had The negative material without lithium of height ratio capacity is superimposed with each other composition；One layer is lithium metal, one layer be height ratio capacity the negative pole material without lithium The bed of material, closely amplexiforms between them.

2. lithium battery negative pole as claimed in claim 1, it is characterised in that：The negative pole without lithium with height ratio capacity Material is silicon, metallic tin, metallic aluminium, metallic antimony, tin-oxide, ferriferous oxide, nickel oxide, cobalt/cobalt oxide, copper oxygen One kind in compound, molybdenum oxide, titanium oxide, barium oxide, tungsten oxide, niobium oxide, cerium oxide or two kinds More than.

3. the preparation method of the lithium battery negative pole described in a kind of claim 1 or 2, it is characterised in that：First in collector Surface prepares negative electrode material layer of the height ratio capacity without lithium, then in negative electrode material layer of the height ratio capacity without lithium away from collector One side surface prepares metallic lithium layer.

4. a kind of preparation method of lithium battery negative pole as claimed in claim 3, it is characterised in that：As negative current collector Material can be copper, nickel, iron or stainless steel；Shape can be netted or sheet.

The method that the height ratio capacity employing of the negative electrode material layer without lithium is prepared in collection liquid surface is electrochemical process, rubbing method, thermal evaporation One or two or more kinds in method, magnetron sputtering method or ion beam sputtering；

The method for preparing metallic lithium layer in the negative pole can be in mechanical roll-in, sputter coating, ion film plating or vacuum evaporation Plant or more than two kinds.

5. preparation method as claimed in claim 4, it is characterised in that：In the negative pole lithium metal with without lithium titanate cathode material Mass ratio is 1:10-11:10.

6. the application of the lithium battery negative pole described in a kind of claim 1 or 2, it is characterised in that：The negative pole with do not contain lithium source Positive pole composition secondary cell, between negative pole and positive pole, containing only allowing the barrier film that passes through of lithium ion, and electrolyte.

7. the application of lithium battery negative pole as claimed in claim 6, it is characterised in that：The described positive electrode without lithium source Can be metal oxide or elemental sulfur；

Described metal oxide cathode material be containing Sn, Co, Fe, Ni, Cu, Mo, Mn, Ti, V, W, Nb, The oxide of one or two or more kinds metallic element in Ce；

Described elemental sulfur is one or more in refined sulphur, sublimed sulfur or sedimentation sulphur.

8. the application of lithium battery negative pole as claimed in claims 6 or 7, it is characterised in that：The described positive pole without lithium source Preparation process be, collection liquid surface use electrochemical method, coating, thermal evaporation, magnetron sputtering or ion beam sputtering system The standby positive pole without lithium source, forms pole piece；

Material as plus plate current-collecting body can be aluminium, copper, nickel, iron or stainless steel, and shape can be netted or sheet.

9. the application of lithium battery negative pole as claimed in claim 6, it is characterised in that：The diaphragm material can be macromolecule Polymer or inorganic compound；

The high molecular polymer is polyethylene, polypropylene, Kynoar-hexafluoropropene, polyacrylonitrile, polymethylacrylic acid The compound of one or two or more kinds in methyl esters, polyvinyl chloride, polyethylene glycol oxide；

The inorganic compound is Li_3xLa_2/3-xTiO₃(0.04<x<Or Li 0.17)₁₄ZnGe₄O₁₆Or Li_1+xA_{2- x}B_x(PO₄)₃(A=Ti, Ge, B=Al, Ga, Sc, In, Y, 0≤x≤0.7) or Li_5+xLa_3-xA_xM₂O₁₂(A=Ba, Sr, M=Zr, Ta, Nb, Sb, Bi, 0≤x≤2) or xLi₂S-(1-x)P₂S₅(0<x<Or xLi 1)₂S-(1-x)SiS₂(0<x<1) or Li₁₀GeP₂S₁₂Or Li₄GeS or Li₃Zn_0.5GeS₄Or Li_3.25Ge_0.25P_0.75S₄Or Li_3.4Si_0.4P_0.6S₄Or Li_4.8Si_0.2Al_0.8S₄ Or Li₆PS₅The compound of one or two or more kinds in X (X=Cl, Br or I) or nitrogen lithium phosphate.

10. the application of lithium battery negative pole as claimed in claim 6, it is characterised in that：The electrolyte can be organic electrolysis Liquid, gel electrolyte or solid electrolyte；

The electrolyte is made up of solvent and lithium salts；Solvent is glycol dimethyl ether, 1- dioxolanes, tetrahydrofuran, diethylene glycol (DEG) two One kind in methyl ether, tetraethylene glycol dimethyl ether, ortho-xylene, ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate or two kinds Mixed solvent above；Lithium salts is lithium hexafluoro phosphate, LiBF4, hexafluoroarsenate lithium, lithium perchlorate, trifluoromethyl sulphur The mixing lithium salts of one or two or more kinds in sour lithium, bis trifluoromethyl sulfimide lithium；

The gel electrolyte is made up of polymer and organic electrolyte；Wherein, polymer can be Kynoar-hexafluoro third The mixing of one or two or more kinds in alkene, polyacrylonitrile, polymethyl methacrylate, polyvinyl chloride, polyethylene glycol oxide Thing；The solvent of organic electrolyte can be glycol dimethyl ether, 1- dioxolanes, tetrahydrofuran, diethylene glycol dimethyl ether, four One or more mixed in glyme, ortho-xylene, ethylene carbonate, dimethyl carbonate, methyl ethyl carbonate Bonding solvent；The lithium salts of organic electrolyte can be lithium hexafluoro phosphate, LiBF4, hexafluoroarsenate lithium, lithium perchlorate, three The mixing lithium salts of one or two or more kinds in methyl fluoride Sulfonic Lithium, bis trifluoromethyl sulfimide lithium；

The solid electrolyte is xLi₂S-(1-x)P₂S₅(0<x<1)、xLi₂S-(1-x)SiS₂(0<x<1)、Li₁₀GeP₂S_12、 Li₄GeS₄、Li₃Zn_0.5GeS₄、Li_3.25Ge_0.25P_0.75S₄、Li_3.4Si_0.4P_0.6S₄、Li_4.8Si_0.2Al_0.8S₄、Li₆PS₅X (X=Cl, Br, I), Li_3xLa_2/3-xTiO₃(0.04<x<0.17)、Li₁₄ZnGe₄O₁₆、Li_1+xA_2-xB_x(PO₄)₃(A=Ti, Ge, B=Al, Ga, Sc, In, Y, 0≤x≤0.7), Li_5+xLa_3-xA_xM₂O₁₂(A=Ba, Sr, M=Zr, Ta, Nb, Sb or Bi, 0≤x≤2), nitrogen phosphorus The compound of one or two or more kinds in sour lithium.