Surface Selenization of NiCo-Layered Double Hydroxide Nanosheets for High-Performance Supercapacitors

Due to their unique spatial structures, layered double hydroxides (LDHs) have been considered as prospective electrode materials for supercapacitors. In this work, several NiCo-LDH materials are obtained via a facile selenization process. This can improve the conductivity and reduce the electrochemical impedance of the samples. The 0.4Se-NiCo-LDH materials deliver a specific capacitance of 1396 F/g at 1 A/g. The capacity retention rate can reach 91.38% after 10,000 cycles. In addition, using the prepared materials as a positive electrode, an asymmetric supercapacitor is constructed. It offers an energy density of 60 Wh/kg at a power density of 2700 W/kg, demonstrating that the synthesized samples possess promising applications in future flexible energy-storage systems.