Mesoporous Silicon Anodes by Using Polybenzimidazole Derived Pyrrolic N-Enriched Carbon toward High-Energy Li-Ion Batteries

The silicon anode holds great potential for next-generation lithium-ion batteries in view of its high gravimetric capacity and natural abundance. The main challenges associated with silicon are the structural degradation and instability caused by huge volume change upon cycling. We report herein polybenzimidazole (PBI) derived pyrrolic N-enriched carbon as an ideal encapsulation onto microsized silicon spheres, which is achieved by an aerosol-assisted assembly combined with a simple physisorption process. The new polymer derived carbon endows silicon with the structural and compositional characteristics of intrinsic high electronic conductivity, abundant pyrrolic nitrogen, and structure robustness. The resulting mesoporous Si-PBI carbon composite exhibits excellent lithium storage performance in terms of high reversible specific capacity of 2172 mAh g –1, superior rate capability (1186 mAh g –1 at 5 A g –1 ), and prolonged cycling life. As a result, a fabricated Si/LiCoO 2 full battery demonstrates high energy density of 367 Wh kg –1 as well as good cycling stability for 100 cycles.