Ni(OH)2/NiSe Nanoparticles Supported on Carbon Microspheres for Long‐Life and High‐Performance Asymmetric Supercapacitors

Abstract The application of Ni‐MOF in supercapacitors has received widespread attention, but its poor conductivity and bad stability hinder its application. Therefore, Ni‐MOF derived CMs@Ni(OH) 2 /NiSe with a core‐shell structure was designed. Here, carbon microspheres (CMs) were explored as the conductive substrate to enhance the stability and in situ prepared Ni‐MOF was anchored on the surface of CMs. Then, alkali‐treatment and selenylation were carried out on CMs@Ni−MOF to improve stability and conductivity. The obtained core‐shell nanostructure material possesses a high contact area, excellent synergistic effect and can provide more reactive active sites. The prepared CMs@Ni(OH) 2 /NiSe shows a higher specific capacitance (2106 F g −1 ) and excellent cycling performance with a capacitance retention of 95 % after 30000 cycles. Furthermore, the assembled CMs@Ni(OH) 2 /NiSe//AC device delivers a high energy density of 70.84 Wh kg −1 at the power density of 756.8 W kg −1 and maintains 100 % of the initial capacitance after 40000 cycles.