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

Graphical Ni-MOF derived CMs@Ni(OH) 2 /NiSe with a core-shell structure was designed. The obtained core-shell nanostructure material possesses a high contact area, excellent synergistic effect and can provide more reactive active sites. 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.