Facile Synthesis of CoWO4 Nanosheet Arrays Grown on Nickel Foam Substrates for Asymmetric Supercapacitors

Well-aligned CoWO4 nanosheet arrays grown on nickel foam substrates have been fabricated by using a facile hydrothermal process. The interconnected CoWO4 nanosheets with abundant open spaces are uniformly deposited on the skeleton of the nickel foam. When investigated as binder-free electrodes for supercapacitors, the CoWO4 nanosheet arrays exhibit a specific capacitance of 1127.6Fg(-1) at 1Ag(-1) and remarkable cycle performance. Moreover, an asymmetric supercapacitor (ASC) is assembled by using CoWO4 nanosheets and activated carbon as the positive electrode and negative electrode, respectively. The ASC device delivers a maximum energy density of 48Whkg(-1) at a power density of 365Wkg(-1). The results demonstrate that CoWO4 nanosheet arrays could be potential electrode materials for energy-storage systems.