Three-dimensional flower-like Co(OH)2 microspheres of nanoflakes/nanorods assembled on nickel foam as binder-free electrodes for High performance supercapacitors

•3D flower-like Co(OH)2 microspheres are successfully assembled on nickel foam.•The Co(OH)2 microspheres exhibited homojunctions of nanoflakes/nanorods.•Binder-free electrodes deliver high area specific capacitance and rate capability.

Three-dimensional (3D) flower-like Co(OH)2 microspheres based on nanoflakes/nanorods are successfully assembled on nickel foam by a one-step hydrothermal method. The as-obtained Co(OH)2/Ni foam composites exhibit multidirectional structures with tertiary nanorods (0.5–1.2 µm in length, 25–40 nm in diameter) growing on the secondary nanoflakes (10 µm in diameter) and forming a highly dense film on the Ni foam. The composites display superior supercapacitor performance with high specific capacitance (1350 F g−1 and 10.4 F cm−2 at 30 mA cm−2) and excellent rate capability, suggesting its promising application as an efficient electrode for electrochemical capacitors.

Graphical abstract3D homojunction microspheres of Co(OH)2 nanoflakes/nanorods are successfully assembled on Ni foam. The as-obtained Co(OH)2 microspheres exhibit excellent specific capacity and rate performance. Figure optionsDownload full-size imageDownload as PowerPoint slide