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, Fe3N/N-doped multilayer graphene (Fe3N/N-mG) was prepared by Fe-catalyzed graphitization of phenanthrene and a post-nitridation process. The well-dispersed Fe3N 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 cm2 s–1) when used as anode materials in LIBs. The optimum Fe3N/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 Fe3N, 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.