Lithium-supplementing slurry for anode, anode and lithium secondary battery
The present invention provides a method of supplementing lithium for an anode used for lithium secondary battery. Particularly, the present invention relates to lithium-supplementing slurry and a method for preparing the same, as well as an anode prepared with the slurry and a lithium secondary battery including the same. In the present invention, the prepolymer is used as a binder for supplementing lithium, the process for preparing the prepolymer is easy to operate and has low cost; the lithium-supplementing method using said prepolymer is easy to operate and has low cost, and it is easy to control the amount of lithium supplemented.
1. A lithium-supplementing slurry for an anode, consisting of a lithium metal powder, a prepolymer and an optional non-aqueous organic solvent, the lithium-supplementing slurry is applied to be coated on the anode which is prepared in advance, a mass ratio of the lithium metal powder and prepolymer is between 2:1 and 1:100, the prepolymer is synthesized from prepolymer monomer through a prepolymerization reaction, the prepolymer monomer is at least one selected from the group consisting of alkyl acrylate, aliphatic alkene, cyanide-containing alkene, polyurethane acrylate and epoxyalkane compounds;
a viscosity average molecular weight of the prepolymer is between 500 and 15000; and
the optional non-aqueous organic solvent is at least one selected from the group consisting of ester, sulfoxide, amide, ketone, fluoroalkanes and fluoro carbonate.
2. The slurry of claim 1 , wherein a mass of prepolymer is 5˜95% of total mass of said slurry.
3. The slurry of claim 1 , wherein the mass of the non-aqueous organic solvent is 20˜89% of total mass of said slurry.
4. The slurry of claim 1 , wherein the non-aqueous organic solvent is at least one solvent selected from the group consisting of ethyl acetate, N,N-dimethyl formamide, N,N-dimethyl acetamide, dimethyl sulfoxide, acetone, N-methylpyrrolidone, ethylene carbonate, methyl ethyl carbonate, dimethyl carbonate, fluoro n-hexane, fluoro cyclohexane, fluoro ethylene carbonate and propylene carbonate.
5. The slurry of claim 1 , wherein the anode comprises an anode active material which is at least one material selected from a carbon based material, a tin based material and a silicon based material.
6. The slurry of claim 5 , wherein the carbon based material is at least one selected from the group consisting of natural graphite, artificial graphite, meso-carbon microbeads, amorphous graphite, hard carbon and soft carbon.
7. The slurry of claim 1 , wherein the average particle size of the lithium metal powder is less than 200 μm.
8. The slurry of claim 1 , wherein the prepolymer monomer is at least one selected from the group consisting of methyl methacrylate, and copolymer of methyl methacrylate and acrylonitrile.
9. The slurry of claim 1 , wherein the reaction time of prepolymerization is between 0.1˜48 hours.
10. The slurry of claim 1 , wherein the prepolymerization is performed at a temperature between −15° C. and 150° C.
11. The slurry of claim 1 , wherein an initiator is added during the prepolymerization.
12. The slurry of claim 11 , wherein the initiator is at least one selected from the group consisting of 2-hydroxy-2-methylpropiophenone, diphenylmethanone compounds, azo compounds, preoxide compounds and redox compounds.
13. The slurry of claim 12 , wherein the initiator is at least one selected from the group consisting of azo-bis-iso-butyronitrile (AIBN), azo-bis-isoheptonitrile, dimethyl azobisisobutyrate (AIBME), hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, benzoyl peroxide, tert-butyl benzoyl peroxide, methyl ethyl ketone peroxide and diacyl peroxide.
14. The slurry of claim 4 , wherein the non-aqueous organic solvent is dimethyl carbonate.