Etching strategy synthesis of hierarchical Ni-Mn hydroxide hollow spheres for supercapacitors

Hierarchical hollow structures have been shown excellent performance in supercapacitors. Herein, hierarchical Ni-Mn hydroxide hollow spheres are successfully prepared by an etching strategy. NiMn-glycerate solid spheres are first obtained as templates. After treatment in the mixed solvents of 1-methyl-2-pyrrolidone and water, NiMn-glycerate templates are etched to form hierarchical Ni-Mn hydroxide hollow spheres. Owing to the advantages of hierarchical hollow structures and large surface area, Ni-Mn hydroxide as electrode material manifests a specific capacity of 1680 F g(-1) at 2.0 A g(-1), and it maintains 1068 F g(-1) at 15 A g(-1). Meanwhile, a diminished specific capacity of only 3.4 % is achieved over 5500 cycles at 10 A g(-1). Furthermore, the fabricated asymmetric supercapacitor comprising of Ni-Mn hydroxide and activated carbon demonstrates a specific energy of 42.8 Wh kg(-1) at 1703 W kg(-1), indicating as a promising electrode material for high performance supercapacitors.

Automated summary

Hierarchical Ni-Mn hydroxide hollow spheres were successfully prepared by an etching strategy, showing excellent performance as electrode material in terms of specific capacity and cyclic stability. The asymmetric supercapacitor fabricated using Ni-Mn hydroxide and activated carbon exhibited a high specific energy, demonstrating its potential as a promising electrode material for high-performance supercapacitors.