Developing Emulsion-Templated Silicon/Carbon Anodes with Reduced Graphene Oxide for Lithium Ion Batteries

Silicon (Si) is considered as one of the most promising candidates for next-generation lithium ion battery anodes owing to its superior theoretical capacity. However, Si suffers from a dramatic volume change during lithiation and delithiation, leading to pulverization and capacity decay. We report a simple oil-in-water emulsion-templating method to successfully fabricate high capacity and stable silicon/carbon anodes by directing Si and carbon to desired spatial locations. Because carbon does not contribute to capacity, we minimize the total amount of carbon in our anodes by using a mixture of carbon black (CB) and reduced graphene oxide (RGO) as the conducting phase. The low percolation threshold of the RGO reduces the anode impedance effectively. With 1 wt% RGO, the electrochemical half-cell tests using this structured Si/CB/RGO anodes show great improvements of capacity and retention after 50 cycles at a cycle rate of C/5 compared to the Si/CB control anodes. Emulsion-templating is a scalable colloidal principle based method for forming electrodes for rechargeable batteries.