▎ 摘　　要

Transition metal oxides (TMOs) such as nickel cobaltite (NCO) and magnetite (Fe3O4) with rich electroactive sites are promising anode materials for sodium-ion batteries (NIBs). However, these materials suffer from large volume change during charge/discharge, poor electron conductivity and severe aggregation of TMO nanoparticles. Here, we report an approach to improve the electrochemical performance of NCO and Fe3O4 by stabilizing them on three-dimensional (3D) nitrogen-doped holey graphene (N-HG), forming NCO@N-HG and Fe3O4@N-HG composite materials, respectively. The thin graphene sheets in both composites facilitate the electron transport and buffer the volume changes, while the interconnected 3D macroporous network with a pore size in the range of several micrometers, combined with the nanopores in the N-HG provide pathways for rapid ion transport. As expected, both composites showed high specific capacities, rate capability and cycling performance in NIBs. The good electrochemical performance of the electrode material indicates that using N-HG to support NCO and Fe3O4 particles is an effective approach towards developing high-performance anode materials for NIBs.