Engineering MXene-Fe MOF interfaces through in-situ growth for high-performance hybrid supercapacitors

Metal-organic frameworks (MOFs) and two-dimensional (2D) MXenes have merged as promising electrode materials for energy storage applications, particularly in supercapacitors (SCs). However, their use in pristine forms or as standalone materials is often hindered by intrinsic structural defects, limited redox-active sites, low electrical conductivity, and stability issues. In this study, a novel MXene Fe MOF composite was synthesized, and an in-situ grown electrode material was developed for SC applications. The composite exhibited enhanced surface area and reduced ion-electron diffusion pathways, significantly improving electrochemical performance compared to individual MXene and Fe MOF electrodes. The MXene-Fe MOF electrode demonstrated an impressive specific capacity of approximately 414 mAh g⁻¹ at a current density of 3 mA cm⁻². Additionally, a solid-state MXene-Fe MOF//FeS asymmetric SC device operated within a wide potential window of 1.6 V and achieved specific and volumetric capacities of ~204 mAh g⁻¹ and ~1.9 mAh cm⁻³, respectively, at the same current density. This study offers a robust strategy for synthesizing MXene-MOF composites and fabricating binder-free in-situ grown electrodes to achieve superior electrochemical performance.