Nanosized FexNi2-xP embedded phosphorus-doped carbon nanorods with superior lithium storage performance

Abstract

Novel hybrid transition metal phosphides with elaborate designed architectures are long pursued to improve their lithium-ion storage properties. Here, nanocomposite of FexNi2-xP particles and P-doped carbon (P-C) substrate has been successfully synthesized through a one-step low-temperature phosphidation of Fe2Ni MIL-88 nanorods. In this nanocomposite, the nano-sized FexNi2-xP particles are embedded into the P-doped carbon nanorods substrate, integrating the high capacity of FexNi2-xP and the excellent conductivity of P-doped carbon together. When used as anode material for lithium-ion batteries, the nanocomposite exhibits a high reversible capacity of 775mAhg−1 after 400 cycles at a current density of 100mAg−1. Even at a high current density of 2000mAg−1, a discharge capacity of 360mAhg−1 could still be maintained. This excellent electrochemical performance may be attributed to the nano-sized building blocks of FexNi2-xP particles and the improved conductivity contributed by P-doped carbon substrate as well as the strong interaction between FexNi2-xP and carbon. Furthermore, this strategy of synthesizing the FexNi2-xP/P-C nanorods with metal-organic frameworks as a starting point can be extended to design other bimetallic transition metal phosphides with superior lithium storage properties.