MOF-derived hollow Co(Ni)Se₂/N-doped carbon composite material for preparation of sodium ion battery anode

Hollow and porous three-dimensional Co(Ni)Se₂/N-doped carbon composite particles prepared by a simple process using metal organic framework (MOF) precursors as the template are used as a high-efficiency anode material for sodium ion batteries. The composite material having a regular rhombohedral dodecahedral structure contains the N-doped porous carbon shell and the nano-metal selenide (CoSe₂ and NiSe₂) embedded in the carbon shell. Moreover, the metal selenide has a high capacity density, and the N-doped porous carbon structure can enhance the electrical conductivity and structural stability of the material to suppress volume expansion. Their effective synergistic combination shows excellent electrochemical performance. As the anode of the sodium ion battery, Co(Ni)Se₂@NCC exhibits a very high specific capacity of up to 735.2 mA h g⁻¹ after 100 cycles and superior rate performance. In addition to these, excellent kinetic performance and cycle stability and coulombic efficiency are sufficient to prove that this material has broad prospects in sodium-ion battery anodes.