Lithium Silicide Encapsulated Porous Carbon Thin Films for Lithium Ion Batteries

Lithium ion batteries are critical for renewable energy storage, but their charge capacity, cyclability, and energy and power densities need to be improved in order to meet the current energy storage demands. Silicon has the potential to meet many of these needs, but unfortunately it undergoes a large volumetric change when lithiated and delithiated. This work focused on fabricating a porous carbon thin film that will perfectly encapsulate a lithium silicide particle. When delithiation occurs, a void space will be left that perfectly accommodates the large volumetric changes of silicon the next lithiation step. We successfully fabricated several porous carbon thin films with and without lithium silicide. The most promising films have a composition of 95:5 weight percent polyacrylonitrile: pore former as 10 weight percent solids in dimethylformamide. Future work will be done to prevent the oxidation of lithium silicide. Once this is done, a battery can be built to test the new anode material.