High-performance supercapacitors based ZnMgWO₄ nanostructures: Synthesis, characterization and electrochemical evaluation

Zinc magnesium tungstate nanoparticles (ZnMgWO₄ NPs) were synthesized through a simple hydrothermal route as a novel and eco-friendly electrode material for high-performance supercapacitors. Structural and morphological characterizations using XRD, FTIR, FESEM, EDX, HR-TEM, and SAED confirmed the formation of highly crystalline, pure nanostructures. Electrochemical studies in 6 M KOH revealed excellent capacitive behavior, delivering a high specific capacitance of 1411 F/g at 2 mV/s and 83.9 % capacitance retention after 5000 cycles. EIS analysis showed low solution and charge-transfer resistances of 0.63 Ω and 0.97 Ω, respectively, indicating efficient ion transport. The asymmetric ZnMgWO₄//AC device achieved an energy density of 50.46 Wh/kg and a power density of 837.35 W/kg with 74.8 % capacity retention over 5000 cycles. These findings demonstrate that ZnMgWO₄ nanostructures are promising, low-cost, and sustainable electrode materials for next-generation energy-storage devices.