Co(OH)2 particles decorated Ni3(NO3)1.6(CO3)0.2(OH)4 flower-like composite electrode for high-performance hybrid supercapacitors

The favorable spatial structure and electrical conductivity are beneficial to fast ion diffusion and charge transport for improved electrochemical performance in hybrid supercapacitors systems. Herein, the Ni-3(NO3)(1.6)(CO3)(0.2)(OH)(4)/Co(OH)(2) (NNH/Co(OH)(2)) composite with three-dimensional flower-like structure was successfully synthesized by a simple solvothermal method. Then, the structure, morphology and composition of the as-prepared composites were investigated by XRD, FTIR, XPS, SEM, HRTEM etc. The result of three-electrode testing revealed that the specific capacity of the NNH/Co(OH)(2) electrode (similar to 967.5 C g(-1) at 1 A g(-1)) was approximately 22.16% higher than that of the NNH electrode (similar to 792.0 C g(-1) at 1 A g(-1)). Meanwhile, the composites revealed an excellent rate capability (86% capacity retention at 10 A g(-1)) and good cycling stability. This excellent performance can be attributed to the introduced Co(OH)(2) particles provide a better charge transport ability and increase electrochemical active site. Moreover, the hybrid supercapacitor assembled with NNH/Co(OH)(2) and AC electrodes exhibited a good energy density as well as cycling performance. (C) 2019 Elsevier B.V. All rights reserved.