Pomegranate-like porous NiCo2Se4 spheres with N-doped carbon as advanced anode materials for Li/Na-ion batteries

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 NiCo2Se4 spheres with N-doped carbon (termed as NC@NiCo2Se4) are synthesized by solvothermal method and annealing. Microstructure investigations reveal that the NC@NiCo2Se4 spheres include nano-sized NiCo2Se4 particles as inner core and NiCo2Se4 with the modification of thin-walled N-doped carbon layer as inner/outer shell. The bimetallic NC@NiCo2Se4 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@NiCo2Se4 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.