Core-shell structured Fe2P@TiO2/CNF anode nanocomposite fibers for efficient lithium/sodium-ion storage

Abstract

Herein, a facile way was reported for fabrication of the anode nanocomposites with efficient lithium/sodium storage and excellent cycling stability. Iron phytate nanoparticles embedded in TiO2 (IP/TiO2) was prepared by coaxial electrospinning with the aid of PAN and PVP. N, P-doped Fe2P@TiO2 core-shell carbon nanofibers (Fe2P@TiO2/CNF) was prepared after heat treatment. When Fe2P@TiO2/CNF were introduced as a self-supporting anode in lithium/sodium-ion batteries, Fe2P core supplied high energy density, and N, P-doped carbon fiber could induce the structural defects, facilitate electron transport and improve electrical conductivity. Moreover, TiO2 shell inhibited volumetric expansion and pulverization of Fe2P core and improved the cycling stability of the anode. The Fe2P@TiO2/CNF electrode exhibited a large reversible capacity (LIB: 1175.7 and SIB: 519.8 mAh g−1), excellent cycling ability and outstanding rate performance. As anode in LIBs for Fe2P@TiO2/CNF, capacitance and diffusion control played important roles in Li+ intercalation and deintercalation, simultaneously. When Fe2P@TiO2/CNF anode was used in SIBs, capacitive control behavior occupied a major role and displayed outstanding electrochemical performance. This work offers a possibility for designing anode nanocomposite with outstanding capacity and cycling stability in lithium/sodium-ion batteries.