Sn-MOF/Zn-MOF composite electrode with interfacial synergy for high-performance battery-supercapacitor hybrid devices

Abstract

The growing demand for reliable and high-performance energy storage devices obliges the development of novel materials that can merge high energy density with rapid charge–discharge capability. Hybrid supercapacitors offer this balance, while MOFs are recognized as promising electrode candidates due to their high surface area and tuneable structure. In this study, a Zn-MOF/Sn-MOF composite framework was synthesized and characterized thoroughly. Electrochemical analysis using CV, GCD, and EIS in both three- and two-electrode assemblies demonstrated that the composite exhibits significantly better performance than the individual pristine MOFs. The Zn-MOF/Sn-MOF//AC device exhibited a specific capacity of 356 C g⁻¹ at 0.6 A g⁻¹. Correspondingly, the maximum energy and power densities of 79.2 Wh kg⁻¹ and 4000 W kg⁻¹, respectively, were achieved. Moreover, the semi-empirical modelling navigation provided insights into the charge storage mechanism, confirming a synergistic effect in the composite. These findings highlight the potential of Sn-MOF/Zn-MOF as a high-performance electrode material for bridging the gap between batteries and supercapacitors.