Controlled Synthesis of Fe₃N Sandwiched in Nitrogen-Doped Multilayer Graphene as an Anode Material for Lithium-Ion Batteries

Iron nitride, with a high theoretical capacity and excellent electrical conductivity, has emerged as a promising high-rate anode material for lithium-ion batteries (LIBs). However, its commercial viability is still hindered by poor cycling stability resulting from severe volume changes upon cycling. To address this shortcoming, Fe 3 N/N-doped multilayer graphene (Fe 3 N/N-mG) was prepared by Fe-catalyzed graphitization of phenanthrene and a post-nitridation process. The well-dispersed Fe 3 N nanocrystals, with a size of ca . 5–10 nm, were spatially sandwiched in the N-doped multilayer graphene with a controlled thickness of 3.5–10 nm and open pore channels, showing abundant accessible active sites, robust structural stability, and high electron/Li + transportation ability (2.1 S cm –1, 2.39 × 10 –12 cm 2 s –1 ) when used as anode materials in LIBs. The optimum Fe 3 N/N-mG delivered exceptional capacities of 590 mA h g –1 at 0.1 C and 412 mA h g –1 at 5 C after 30 cycles, and a capacity retention of 530 mA h g –1 at 0.1 C after 600 cycles, surpassing the pure Fe 3 N, graphene, and many previously reported metal–nitride-based anodes. This work offers an in situ metal catalysis of polycyclic aromatic hydrocarbons and a subsequent post-nitridation strategy for the facile preparation of high-performance metal nitride/graphene electrodes for LIBs.