Three-Dimensional Porous Carbon-Silicon Frameworks as High-Performance Anodes for Lithium-Ion Batteries

As a promising anode material for lithium-ion batteries, Si is still facing great challenges owing to the rapid capacity fade, which is mainly caused by the large volume changes during cycling. We have rationally designed novel 3D porous carbon-silicon frameworks by self-assembly of the phenol formaldehyde resin and triblock copolymer. The triblock copolymer acts as both structure-directing agent and template for the formation of a uniform carbon shell and the generation of bimodal porous structures. The as-fabricated porous carbon-silicon (PC-Si) hybrid exhibits an initial capacity of 1868 mA hg(-1) with a columbic efficiency of 41%. The columbic efficiency rapidly increases to 99% and the capacity remains at approximate to 1000 mAhg(-1) after 100 cycles suggesting a much more stable cycling and enhanced capacitance compared to Si with direct carbon coating. Such an excellent electrochemical performance is attributed to the formation of continuous mesoporous structures in the exclusive 3D conductive frameworks.