Engineering Rice Husk into a High-Performance Electrode Material through an Ecofriendly Process and Assessing Its Application for Lithium-Ion Sulfur Batteries

High-capacity and cycle-stable SiOx/C composite anodes for Li-ion batteries (LIBs) were synthesized from rice husk (RH) using an ecofriendly, one-step pyrolysis process that takes full advantage of both the silica and organic components of RH. The process–property–performance relationship for this process was investigated. Pyrolysis of RH at a sufficiently high temperature (1000 °C) results in a C scaffold with a low surface area, high electronic conductivity, and embedded SiOx nanoparticles that are highly active toward lithiation, enabling high rate capability along with outstanding cycle stability for LIB applications. A SiOx/C anode delivering a specific capacity of 654 mAh g–1 and retaining 88% capacity (99.8% CE) after 1000 cycles was demonstrated. Higher capacities, up to 920 mAh g–1, can be achieved by adding a Si-containing polymer coating on RH prior to pyrolysis. The SiOx/C anodes demonstrated considerable promise for Li metal-free Li-ion sulfur batteries.