Control over large-volume changes of lithium battery anodes via active-inactive metal alloy embedded in porous carbon
Large volume changes and limited access to redox sites of high capacity anode materials are great challenges. Although, various strategies were adopted but still results are far from required values for their practical usage. Here, we have designed a unique structure to prevent surface reaction and structural disintegration meanwhile intrinsic conductivity is improved to involve all redox sites in conversion reaction. CoSnx@C-PAn hybrid was synthesized through aqueous chemical route, Co doping in tin make accessible all redox sites by faster conduction of electrons while its hard nature relaxes internal stress, carbon shell prevents surface reaction and brings well control on solid electrolyte interface (SEI) film by maintaining barrier between electrode surface and electrolyte and nitrogen doped porous carbon provides faster diffusion of Li+ deep in electrode make possible high mass loadings and conduction highway for electrons. Furthermore, porous carbon also provides room to compensate volume expansion and keeps electrode structure stable. Because of its unique structure hybrid shows excellent reversible capacity of 2044mAh/g (retention 100%) with mass loading of 3.8mg/cm2 along with long cyclic life up to 1000 cycles and bears high rate capability (20A/g).We believe that present study makes possible the use of high capacity materials in applications.