Methods for prelithiation of silicon containing electrodes

Abstract

The present application describes a method of forming an energy storage device that directly adds a lithium layer (such as a lithium foil or otherwise deposited lithium) into the cell stack during cell assembly for prelithiating. The method includes providing a silicon-based anode, providing a cathode, positioning a separator between the anode and the cathode, and disposing a lithium layer between the silicon-based anode and the separator, such that the lithium layer is in contact with the anode.

1 - 19 . (canceled) 
     
     
         20 . A method of forming an energy storage device comprising:
 providing a Si-based anode;   providing a cathode;   providing a separator;   prelithiating the separator prior to forming of the energy storage device, the prelithiating comprising applying a lithium layer on a surface of the separator;   positioning the prelithiated separator between the anode and the cathode, such that the lithium layer is in contact with the anode; and   combining the separator, the anode, and the cathode to form the energy storage device.   
     
     
         21 . The method of  claim 20 , wherein applying the lithium layer comprises depositing lithium on the surface of the separator. 
     
     
         22 . The method of  claim 21 , wherein depositing the lithium on the surface of the separator comprises spraying powder lithium onto the surface or sputtering lithium onto the surface. 
     
     
         23 . The method of  claim 20 , wherein applying the lithium layer comprises applying a lithium foil to the surface of the anode. 
     
     
         24 . The method of  claim 20 , wherein the lithium layer comprises an amount of lithium for 10% to 30% of anode capacity. 
     
     
         25 . The method of  claim 20 , wherein the separator is resistant to reduction by the lithium. 
     
     
         26 . The method of  claim 20 , wherein the separator is made of a material selected from the group consisting of polyolefin, cellulose, and combinations thereof. 
     
     
         27 . The method of  claim 26 , wherein the polyolefin is selected from polyethylene, polypropylene, and combinations thereof. 
     
     
         28 . The method of  claim 20 , wherein the prelithiated separator further comprises a surface coating between the surface of the prelithiated separator and the lithium layer. 
     
     
         29 . The method of  claim 20 , further comprises forming a safety layer on at least the lithium layer. 
     
     
         30 . The method of  claim 29 , wherein the safety layer comprises a polymeric material. 
     
     
         31 . The method of  claim 30 , wherein the polymeric material is selected from the group consisting of polyvinylidene fluoride (PVDF), poly(methyl methacrylate) (PMMA), styrene butadiene rubber (SBR), poly(acrylic acid) (PAA), poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO), and combinations thereof. 
     
     
         32 . The method of  claim 20 , further comprises applying a clamping pressure to the energy storage device across the anode, the cathode, and the prelithiated separator. 
     
     
         33 . The method of  claim 32 , wherein the clamping pressure is between 20 psi and 160 psi. 
     
     
         34 . The method of  claim 20 , wherein the anode is a Si-dominant anode. 
     
     
         35 . The method of  claim 20 , wherein the anode comprises a composite material film comprising:
 greater than 0% and less than 90% by weight of silicon particles, and   greater than 0% and less than 90% by weight of one or more types of carbon phases, wherein at least one of the one or more types of carbon phases is a to a greater extent continuous phase that holds the composite material film together such that the silicon particles are distributed throughout the composite material film.   
     
     
         36 . The method of  claim 35 , wherein at least a portion of the composite material film has a self-supported monolithic structure.