Highly dispersed CoWO4 nanoparticles anchored on CNT as electrode for hybrid supercapacitor by microwave-assisted hydrothermal synthesis

To improve the electrochemical performance of cobalt tungstate (CoWO4) to serves as electrode materials for supercapacitors, a facile microwave-assisted hydrothermal method was developed, which successfully anchored highly dispersed CoWO4 nanoparticles on carbon nanotubes (CNTs). The as-prepared CoWO4/CNT composites has much smaller particle size of CoWO4 nanoparticles with enhanced conductivity due to the addition of CNTs. As a result, the as-prepared CoWO4/CNT showed a high-specific capacity (842.0 C.g(-1) at a current density of 1 A.g(-1) and 506.0 C.g(-1) at 10 A.g(-1)), a wide potential window (0.90 V), and exceptional cycling stability of reverse capacity growth (maximum retention of 322.9% after 4651 cycles and 254.4% after 20,000 cycles at 30 A.g(-1)). The outstanding performance is attributed to the well dispersion of nano-sized CoWO4 particles, favorable orientation, the presence of oxygen vacancies, and the heterogeneous interface with CNTs. The results suggest that CoWO4/CNT composites are highly promising as electrode materials for next-generation supercapacitors.