Ultra-high-performance zinc-ion supercapacitor based on single-copper molybdate urchins

Lithium-ion (Li-ion) and sodium-ion (Na-ion) hybrid supercapacitors have emerged as promising energy storage systems, offering a balance between high power and energy density. However, their practical implementation is constrained by safety concerns and high production costs. Zinc-ion hybrid supercapacitors (ZHSCs) have gained significant attention as a viable alternative due to their intrinsic safety, cost-effectiveness, and natural abundance. Herein, we report the successful synthesis of urchin-like copper molybdate on carbon cloth (CuMoO₄/CC) as a high-performance electrode material for ZHSCs. The CuMoO₄/CC electrode exhibited an exceptional specific capacitance of 2200 F g⁻¹ at 1 A g⁻¹ in a three-electrode configuration, demonstrating excellent charge storage capability. When assembled an aqueous ZHSC, the CuMoO₄/CC electrode achieved excellent specific capacitance of 560 F g⁻¹ at 1 A g⁻¹, remarkable energy density of 263.8 Wh kg⁻¹ and a power density of 998 W kg⁻¹. Furthermore, a flexible quasi-solid-state ZHSC based on CuMoO₄/CC employing a gel electrolyte was also studied and it delivered superior specific capacitance of 390 F g⁻¹ at 1 A g⁻¹, a high energy density of 195 Wh kg⁻¹ at a power density of 875 W kg⁻¹, all these findings underscoring its potential for next-generation flexible energy storage applications. These findings provide valuable insights into the development of high-performance ZHSCs, paving the way for their practical implementation in advanced energy storage technologies.