One pot synthesis of nickel foam supported self-assembly of NiWO4 and CoWO4 nanostructures that act as high performance electrochemical capacitor electrodes

In this work, we report a facile one-step hydrothermal approach to synthesize NiWO4 and CoWO4 nanostructures on nickel foam as binder-free electrodes for use as supercapacitors. The as-synthesized materials showed excellent electrochemical performance, with a high specific capacitance of 797.8 F g(-1) and 764.4 F g(-1) at a current density of 1 A g(-1) after 3000 cycles. On increasing the current density by 20 times, the rate capabilities still maintained 55.6% and 50.6% of the original value for NiWO4/Ni foam and CoWO4/Ni foam, respectively. Moreover, both of these materials exhibited outstanding cycling stability, the 6000th cycle at 50 mV s(-1) demonstrated 2.06 and 2.81 times better capacitance than the initial cycles for NiWO4/Ni foam and CoWO4/Ni foam, respectively. To our knowledge, this capacitance performance is better than any previously reported value for these materials and is a consequence of the highly evolved surface area/microstructure of the materials formed by this technique.