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.