Development of Bimetallic MOF with reduced bandgap for high-performance asymmetric supercapacitors

Abstract

Metal-organic framework (MOF) is a novel class of active material, a probable candidate for high-performance electrochemical energy storage devices due to their porous structure, enormous surface area, versatility, and structural tunability. Herein, we synthesized bimetallic MOFs with different concentrations of Ni or Co in Ag-MOF via a facile one-pot synthesis method and utilized it as a battery-type electrode in a hybrid supercapacitor. The flake-like synthesized materials exhibit outstanding electrochemical properties, specifically, Co₁Ag₃-MOF demonstrates the highest specific capacity/capacitance of 1323 C g⁻¹ (2646 F g⁻¹) at a current density of 1 A g⁻¹ and maintained 79.5 % of initial capacity even at higher current density. Moreover, the assembled asymmetric supercapacitor device (Co₁Ag₃-MOF//AC) achieves the highest energy density of 75.63 W h kg⁻¹ with a power density of 566.4 W kg⁻¹ at 1 A g⁻¹, manifesting reliable cyclic durability by retaining 88.35 % of its initial capacity and 92.45 % coulombic efficiency after 12,000 cycles. Moreover, the assembled hybrid coin cell can operate the commercially available calculator for 96 min. Based on both experimental and theoretical calculations, the optimized electronic structure of the Co₁Ag₃-MOF interface promotes electron transmission pathways and synergizes high redox activity, resulting in improved electrochemical performance. This study provides new insights into π-π conjugated materials with reduced band gap for further use in next-generation electronics for power supply.