Bimetallic Ni/Co-ZIF-67 derived NiCo2Se4/N-doped porous carbon nanocubes with excellent sodium storage performance

Ni-Co-based zeolitic imidazolate framework (Ni/Co-ZIF-67) derived NiCo2Se4/N-doped porous carbon (NiCo2Se4@NPC) nanocubes are used as anode materials of sodium ion batteries (SIBs). The nano size and porous structure of NiCo2Se4 nanocubes accelerate reaction kinetics and relieve volume expansion, and the porous carbon increases the material's electronic conductivity. Moreover, the electrochemical process of the NiCo2Se4@NPC electrode materials is mainly dominated by pseudocapacitive behaviors according to the kinetic studies by cyclic voltammetry. Consequently, NiCo2Se4@NPC nanocubes deliver a high discharge capacity of 462.1 mAh g−1 at 0.1 A g−1 after 70 cycles in SIBs. Even at a high current density of 2 A g−1, the discharge capacity of NiCo2Se4@NPC nanocubes can reach 372 mAh g−1. This study provides a reliable basis for the preparation of bimetallic selenide and helps to promote the development of bimetallic selenide as anode in SIBs.