Synergistic effect of a 1-D (one-dimensional) MnO2/ZnO binary nanocomposite as an advanced electrode for reliable, high-energy-density asymmetric supercapacitors

Abstract

The combined effect of MnO₂ and ZnO provides an effective approach to enhance the electrode materials' surface area and redox characteristics for usage in efficient energy storage devices. In the present work, a 1-D α-MnO₂/ZnO binary nanocomposite was successfully synthesized and evaluated for supercapacitor applications. The α-MnO₂/ZnO electrode exhibited a remarkable capacitance of 650 F g⁻¹ with a current density of 2 A g⁻¹, which is higher than that of pure α-MnO₂ (452 F g⁻¹). Moreover, the fabricated asymmetric supercapacitor device (α-MnO₂/ZnO//AC) delivered an excellent specific capacitance of 156 F g⁻¹ at 1 A g⁻¹ and an impressive energy density of 55.6 Wh kg⁻¹ in a 1.0 M Na₂SO₄ electrolyte. Additionally, the prepared electrode maintained exceptional stability, preserving approximately 96% capacitance after 6000 cycles. These findings show that the α-MnO₂/ZnO nanocomposite effectively enhances redox activity and offers great potential for practical supercapacitor applications.