Phase boundary-enhanced Ni3N–Co3N@CNT composite materials for lithium-ion batteries

Abstract

Metal nitride materials are considered as promising candidates for next-generation lithium-ion secondary battery anode materials owing to their high electrical conductivity and attractive theoretical capacity. In this paper, we reported a synthesis method to grow ultrafine Ni₃N–Co₃N nanoparticles on carbon nanotubes (Ni₃N–Co₃N@CNTs) via a simple hydrothermal reaction and post-ammonization treatment. By virtue of such a unique structure and component, especially the abundant phase boundaries between Ni₃N and Co₃N, when used as anodes for lithium-ion batteries (LIBs), the resultant composites delivered reversible discharge capacity of 553.26 mA h g⁻¹ even after 600 cycles at a current density of 0.4 A g⁻¹. This reversible capacity was remarkably higher than the theoretical capacities of both Ni₃N (424.3 mA h g⁻¹) and Co₃N (421.0 mA h g⁻¹). We believe that this study will provide a new idea to design high-performance anode materials for LIBs via constructing abundant phase boundaries between different components in composites.