Synthesis of three-dimensional honeycomb-like Fe3N@NC composites with enhanced lithium storage properties

Abstract

Iron nitrides have been recognized as attractive anode candidates for lithium ion batteries (LIBs) due to their high theoretical capacities, high tap densities, cost-effectiveness, multiple electron transfer and good ionic diffusion. The strategies of pore structure engineering and carbon coating have been proven to be effective ways to address the critical issues of iron nitrides as anodes for LIBs. Herein, we synthesized a series of Fe3N@NC-x with 3D honeycomb nanostructures by a simple heating-controlled and ammoniation-assisted approach. The Fe3N@NC-x as anodes for LIBs display outstanding lithium storage properties with high reversible capacity of 767.8 mA h g−1 at 0.1 A g−1 and long-term cycling performance (814.5 mA h g−1 at 1 A g−1 over 2000 cycles). Such outstanding properties were attributed to the interconnected conductive pathways (honeycomb walls, hexagonal channels) for rapid ionic/electronic transport, the macro-/meso porous structure for the quick penetration of electrolytes and the accommodation of electrode volume variation during the cycles, meso-/micro porous structure for the additional storage of Li+, and efficient utilization of the Fe3N nanoparticles unifomly distributed through highly conductive interconnected network.