Hydrothermal synthesis of Ni,Co hydroxide nanosheet array on vertically suspended Ni foam for high performance supercapacitors

Abstract

Ni(OH)2 have attracted great attention as pseudocapacitor electrode materials due to its high theoretical capacitance. However, the intrinsic disadvantaged in low electronic conductivity and sluggish ion diffusion kinetics of Ni(OH)2 limit its performance and practical application. Herein, we report a simple hydrothermal method to synthesize Co doped Ni(OH)2 and NiOOH array structure on vertical hanging Ni foam. Compared with traditional hydrothermal methods, vertical hanging Ni foam provide sufficient reaction sites and ensure fully growth of array structure, leading to large mass loading of active materials. The array structure and the wide interlayer spacing due to interlayer embedded CH3COO− together build an effcient ion diffusion path. Morevoer, strong electron exchange between Ni(OH)2 or NiOOH and Ni provide high electrical conductivity at the interface, forming the fast and complete electron transport channel inside the electrode. As a result of robust electrochemical kinetics, NiCoLDH@vNF-12 shows a high capacitive and outstanding rate performance of 952.9 C g−1 at 1 A g−1 and 660.0 C g−1 even at 50 A g−1.