Lewis acid etched NixCo1-xSe2 derived from ZIF-L on CoO nanowires for hybrid-supercapacitors

Abstract The ideas of high effective specific surface area, multi-component and multi-phase synergistic are introduced to construct high-performance and high-stability electrodes. After etching and exchanging with Lewis acid (nickel ion) and annealing selenization, the hierarchical multi-phase NixCo1-xSe2/carbon–nitrogen frameworks (CNFs, Zeolitic-Imidazolate-Framework-L derivatives) on CoO is synthesized. After systematic research, it is found that the concentration and reaction time of the Lewis acid and selenization conditions can directly affect the structure and composition (bimetal) of the electrode. In the optimal electrode, CNFs with the larger effective specific surface area can fully expose the active material to the electrolyte, the bimetal synergy (Ni-Co), and the multiphase synergy ((Ni, Co)Se2 and CoSe2) can effectively enhance the performance. The anode demonstrates a high mass-specific capacity of 207.8 mAh g−1. A hybrid supercapacitor (NixCo1-xSe2/CNFs/CoO@CC//activated carbon) is fabricated and displayed superior performance and stability: high energy density (45.0 Wh kg−1, 800.0 W kg−1), and a cycle retention rate of 98.0% (12,000 cycles). LEDs in parallel were lit up by the devices, showing their practical value and potential.