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

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.