Synergistic Engineering of Carbon Nanotubes Threaded NiSe₂/Co₃Se₄ Quantum Dots with Rich Se Vacancies for High-Rate Nickel-Zinc Batteries

Limited by sluggish reaction kinetics, insufficient electrode utilization and severe volume deformation, designing nickel-based materials with high capacity and rate capability is still a challenge. Herein, a carbon nanotubes threaded NiSe2/Co3Se4 quantum dots embedded in carbon nanospheres with rich Se vacancies both in NiSe2 and Co3Se4 is elaborately designed via MOF template method. The formation mechanism of the Se vacancies is elucidated for the first time, which is ascribed to the release of gas during the decomposition of organic ligand inhibits the ordered arrangement of atoms. The CNT-V-NiCoSe possesses many significant superiorities, such as sufficiently exposed active sites, high electrode utilization, favorable charge-carrier migration, and relaxed structure deformation. Consequently, the CNT-V-NiCoSe electrode shows top-level specific capacity (384 mAh g(-1) at 1 A g(-1)), ultrahigh rate capability (209 mAh g(-1) at 150 A g(-1)) and remarkable cycling durability. The CNT-V-NiCoSe//Zn battery achieves maximum energy density of 615.6 Wh kg(-1) and maximum power density of 81.7 kW kg(-1). Density functional theory calculations elucidate the Se vacancies improve the density of states at Fermi level, facilitates internal charge transfer, and enhances OH- adsorption ability. This study provides guidance for the preparation of high-performance electrode materials with rich vacancies by template method.