Achieving High Volumetric Lithium Storage Capacity in Compact Carbon Materials with Controllable Nitrogen Doping

Although nanostructured/nanoporous carbon and silicon-based materials are a potential replacement for graphite as cost-effective anodes for lithium ion batteries (LIBs), their extremely low packing density leads to considerably reduced volumetric capacities. Herein, a highly compact carbon anode material constructed from sub-2 nm nanosized graphitic domains is reported that exhibits excellent capacity density. By introducing a coordination agent in the synthesis precursors, an unusually high concentration of N-doping (≈26.56 wt%) is achieved, which is mainly confined at the graphitic edges with the pyrrolic-N and pyridinic-N configurations. As further supported experimentally and theoretically, the edge-N dopants, particularly the pyrrolic-N, favor both ion diffusion kinetics and lithium storage via adsorption. Based on the lithiation-state electrode volume, the compact anode shows a capacity density of 951 mAh cm _total ⁻³ that is comparable with Si anodes and surpasses all reported carbon-based anodes, revealing its potential in promoting the performance of future LIBs.