Advanced Supercapacitors Based on α-Ni(OH)₂ Nanoplates/Graphene Composite Electrodes with High Energy and Power Density

In order to solve the lack of energy sources, researchers devote themselves to the study of green renewable and economical supercapacitors. We demonstrate herein that the α-Ni(OH)2 nanoplates/graphene composites are fabricated as active electrodes in supercapacitors with excellent cycling stability, high energy density, and power density. The advantages of graphene can complement the shortcomings of α-Ni(OH)2 nanoplates to compose a novel composite. The α-Ni(OH)2 nanoplates/graphene composite presents a high specific capacitance of 1954 F g–1 at 5 A g–1. The reason for the improving performance is attributed to graphene, which provides an improved conductivity and increased specific surface area by interweaving with α-Ni(OH)2 nanoplates. It is particularly worth mentioning that the assembled asymmetric supercapacitor cells yield a high specific capacitance of 309 F g–1 at 5 A g–1 and light a 2 V LED sustainable for about 7 min, which may bring great prospects for further fundamental research and potential applications in energy storage devices.