3D network structure of Co(OH)2 nanoflakes/Ag dendrites via a one-step electrodeposition for high-performance supercapacitors

•Three-dimensional (3D) mechanically robust Ag dendrites/Co(OH)2 nanoflakes network structure was uniformly synthesized on Ni foam by a one-step electrodeposition method.•3D network structures can provide abundant active sites for electrode reactions and shorten ions diffusion path, which will enhance electrochemical performance.•The combination of Ag dendrites and Co(OH)2 nanoflakes enhances mechanical stability and ensures conductivity of the electrode.•An excellent super-capacitive performance was brought, with a specific capacitance of 2074 F g−1 at 1 A g−1, and an 80.8% capacitance retention after 60,000 charge/discharge cycles at 5 A g−1. Layered Co(OH)2 nanoflakes are regarded as a promising supercapacitor electrode material owing to its high theoretical speicific capacitance, but the application is limited by low electrical conductivity and weak mechanical strength. In this work, we synthesize a three-dimensional (3D) Co(OH)2 network structure supported by Ag dendrites on Ni foam by one-step electrodeposition. This 3D structure delivers an excellent supercapacitive performance with a specific capacitance of 2074 F·g−1 at 1 A g−1, and an 80.8% capacitance retention after 60,000 charge/discharge cycles at 5 A·g−1. The test results indicate that introduction of Ag dendrites can provide ideal conductivity and make the 3D structure more durable. Results of this paper provide a feasible method for the practical application of Co(OH)2 in supercapacitors. [Display omitted]