Facile Synthesis of CoWO 4 Nanosheet Arrays Grown on Nickel Foam Substrates for Asymmetric Supercapacitors

Well‐aligned CoWO 4 nanosheet arrays grown on nickel foam substrates have been fabricated by using a facile hydrothermal process. The interconnected CoWO 4 nanosheets with abundant open spaces are uniformly deposited on the skeleton of the nickel foam. When investigated as binder‐free electrodes for supercapacitors, the CoWO 4 nanosheet arrays exhibit a specific capacitance of 1127.6 F g −1 at 1 A g −1 and remarkable cycle performance. Moreover, an asymmetric supercapacitor (ASC) is assembled by using CoWO 4 nanosheets and activated carbon as the positive electrode and negative electrode, respectively. The ASC device delivers a maximum energy density of 48 Wh kg −1 at a power density of 365 W kg −1 . The results demonstrate that CoWO 4 nanosheet arrays could be potential electrode materials for energy‐storage systems.