Nanosheet-assembled NiCo-LDH hollow spheres as high-performance electrodes for supercapacitors

Layered double hydroxides (LDHs) have been considered as favorable pseudocapacitive electrode materials for supercapacitors due to their tunable layered structure/compositions and low cost. Here, we report the NiCo-LDH hollow spheres prepared with Co-glycerate as the sacrificial template and cobalt source. The hollow spheres are assembled with frizzy NiCo-LDH nanosheets, where the hollow structure can inhibit agglomeration of the LDH nanosheets to expose more active sites and shorten the diffusion path of electrolyte ions. The prepared NiCo-LDH hollow spheres show a high specific capacitance of 1962 F g^-1 at 1 A g^-1 and good capacitance retention rate of 66.4 % at 30 A g^-1. The asymmetric supercapacitors fabricated using NiCo-LDH hollow spheres as positive electrode yields a large energy density 62.9 Wh kg^-1 at the power density of 0.8 kW kg^-1. This research may develop a facile synthesis way to prepare LDH hollow spheres for supercapacitors.