Exploration of Ni-X (O, S, Se) for high performance supercapacitor with long-term stability via solution phase synthesis

[Display omitted] •Exploration of NiSe with triethanolamine via in-situ method.•Selenium wrapped NiO nanotubes with capacitance increment and charge accumulation.•A cone-type platelets nanostructure with greater surface area.•NSE7h nanoplatelet structure exhibits superior electrochemical performance than NO, NS, NSE1h and NSE4h.•The selenium vacancy’s is a great advantageous for efficient transport pathway of electrons and electrolyte ions. Here, we report a simple strategy to grow NiSe architectures vertically on nickel foam (NF) via facile solution-based deposition. The as-synthesized NSE7h core-shell nanoplate structure with a mass loading of 6.4mg/cm−2 can be delivered a high specific capacitance of 2234.84Fg−1 at 10mAcm−2 and outstanding rate capability compared to that of NO (708.52Fg−1), NS (968.22Fg−1), NSE1h (1357.43Fg−1), and NSE4h (1675.87Fg−1). The desirable electrochemical performance was mainly attributed to the component’s synergy assuring rich redox reactions, deposition of selenium on the surface of NiO nanotubes, high conductivity, great specific area and furthermore, rapid ion diffusion distance, with effective transport pathway of electrons and electrolyte ions. The existence of selenium vacancies and versatile synthesis of NiSe architectures would open up a wide range of applications in energy storage and conversion applications including supercapacitors, electrocatalysis, and batteries.