Novel hierarchical yolk-shell α-Ni(OH)2/Mn2O3 microspheres as high specific capacitance electrode materials for supercapacitors

For high performance supercapacitors, novel hierarchical yolk-shell a-Ni(OH)₂/Mn₂O₃ microspheres were controllably synthesized using a facile two-step method based on the solvothermal treatment. The unique a-Ni(OH)₂ based yolk-shell microstructures decorated with numerous interconnected nanosheets and the hetero-composition features can synergistically enhance reactive site exposure and electron conduction within the microspheres, facilitate charge transfer between electrolyte and electrode materials, and release structural stress during OH^? chemisorption/desorption. Moreover, the Mn₂O₃ sediments distributed over the a-Ni(OH)₂ microspheres can serve as an effective protective layer for electrochemical reactions. Consequently, when tested in 1 mol·L^?1 KOH aqueous electrolyte for supercapacitors, the yolk-shell a-Ni(OH)₂/Mn₂O₃ microspheres exhibited a considerably high specific capacitance of 2228.6 F·g^?1 at 1 A·g^?1 and an impressive capacitance retention of 77.7% after 3000 cycles at 10 A·g^?1. The proposed a-Ni(OH)₂/Mn₂O₃ microspheres with hetero-composition and unique hierarchical yolk-shell microstructures are highly promising to be used as electrode materials in supercapacitors and other energy storage devices.