Prelithiated negative electrode, preparation method thereof, and lithium ion battery and supercapacitor comprising the same
The present disclosure provides a prelithiated negative electrode, a preparation method thereof, and a lithium ion battery and a supercapacitor comprising the same. The prelithiated negative electrode comprises: an electrode film which is a solvent-free film-like negative electrode material composed of a negative electrode active material, a lithium-skeleton carbon composite material, a binder and optionally a conductive additive; and a metal current collector, wherein the electrode film is bonded on the metal current collector through a conductive adhesive. The present disclosure provides an effective method of prelithiating a negative electrode, and can effectively improve the first cycle efficiency of a lithium battery comprising a silicon-carbon negative electrode, contributing to increasing the specific capacity and cycle life of the battery. The present disclosure can also increase the energy density of a supercapacitor.
1 . A method of preparing a prelithiated negative electrode wherein the method comprises:
mixing and dispersing a negative electrode active material, particles of a lithium-skeleton carbon composite material, a binder and a conductive additive with a high shear force under a solvent-free condition, wherein the mixing and dispersing is performed through a jet milling process, wherein a high pressure gas used in the jet milling has a dew point of −40° F. to −60° F., a moisture content of less than 15 ppm, and a pressure of 60 to 100 PSI;
extruding and calendering the obtained mixture at a high temperature of 180 to 350° C. into an independent film-like material with a thickness; and
pressure bonding the obtained film-like material onto a current collector,
wherein the negative electrode active material is a negative electrode material for lithium battery, selected from at least one of a silicon-carbon composite material and lithium titanate,
wherein the lithium-skeleton carbon composite material is a microparticle material composed of a carbon-based porous microsphere material having pores with a pore size of 1 to 100 nm and metallic lithium present on the surface of and in the pores of the carbon-based porous microsphere material, and the microparticle material has a particle size D50 of 5 to 20 μm,
wherein the carbon-based porous microsphere material comprises at least one selected from the group consisting of a carbon nanofiber microsphere material and a carbon nanotube microsphere material, wherein the carbon nanofiber microsphere material or the carbon nanotube microsphere material are respectively formed by entangling and agglomerating carbon nanofibers or carbon nanotubes with each other, and the microsphere is full of carbon nanofibers or carbon nanotubes in its interior, with nanoscale pores being present in its interior and on its surface, and
wherein the binder comprises at least one of
carboxymethyl cellulose (CMC);
poly(acrylic acid);
polytetrafluoroethylene (PTFE);
poly(methyl methacrylate) (PMMA); and
poly(ethylene oxide) (PEO).
2 . The method according to claim 1 , wherein a rolling pressure of the pressure bonding ranges from 0.1 to 120 MPa.
3 . The method according to claim 2 , wherein the rolling pressure of the pressure bonding ranges from 50 to 100 MPa.
4 . The method according to claim 1 , wherein the high temperature is 210 to 300° C.
5 . The method of preparing a prelithiated negative electrode according to claim 1 , wherein the metallic lithium in particles of the lithium-skeleton carbon composite material has a content of 10% to 95% by mass.
6 . The method of preparing a prelithiated negative electrode according to claim 1 , wherein the binder has a content of 1% to 5% by mass.
7 . The method of preparing a prelithiated negative electrode according to claim 1 , wherein the conductive additive is selected from the group consisting of carbon black, carbon nanofibers, carbon nanotubes, graphene, and combinations thereof.
8 . The method of preparing a prelithiated negative electrode according to claim 1 , wherein the independent film-like material is bonded on the current collector through a conductive adhesive, and the conductive adhesive comprises at least one selected from the group consisting of an epoxy resin conductive adhesive, a phenolic resin conductive adhesive, a polyurethane conductive adhesive, a thermoplastic conductive adhesive, and a polyimide conductive adhesive.