Pomegranate-like porous NiCo_(2)Se_(4) spheres with N-doped carbon as advanced anode materials for Li/Na-ion batteries

摘要

Design and preparation of dual-role anode materials with extraordinary performance for rechargeable Li/Na-ion batteries (LIBs/NIBs) remains highly challenging.Herein,three-dimensional (3D) pomegranate-like porous bimetallic NiCo_(2)Se_(4) spheres with N-doped carbon (termed as NC@NiCo_(2)Se_(4)) are synthesized by solvothermal method and annealing.Microstructure investigations reveal that the NC@NiCo_(2)Se_(4) spheres include nano-sized NiCo_(2)Se_(4) particles as inner core and NiCo_(2)Se_(4) with the modification of thin-walled N-doped carbon layer as inner/outer shell.The bimetallic NC@NiCo_(2)Se_(4) spheres possess synergistic interaction of Ni/Co atoms to enhance intrinsic conductivity and electrochemical activity,unique pomegranate-like structure with an inner void space and robust shell to mitigation volume expansion,and intimate contact of N-doped carbon layer to improve interface effect and accelerate conversion kinetics.As anode materials,the NC@NiCo_(2)Se_(4) exhibits superior lithium/sodium storage performances (1401.6 and 794.8 mA h g^(-1)at current density of 0.5 and 5 A g^(-1)after 500 cycles for LIBs as well as 433.9 mA h g^(-1)at 3 A g^(-1)after 1000 cycles and a high capability of 306.6 mA h g^(-1)at 20 A g^(-1)for NIBs).This work represents an impressive strategy for future research of bimetallic selenides as anode materials for advanced high-performance LIBs/NIBs.