Co-BDC metal organic framework and fluoride free process synthesized partially etched MXene composite for electrochemical energy storage applications

Abstract Poor electrical conductivity and sluggish charge transport often limit the electrochemical performance of metal–organic frameworks (MOFs). Here, a cobalt- benzene-1,4-dicarboxylate-dimethylformamide, [Co(BDC)DMF] n MOF, was synthesized via a solvothermal route and integrated with alkali assisted partially etched MXene (Ti 3 C 2 T x ; T = -O, -OH, x = 1–4) to develop a high-performance composite electrode. Compared to conventional HF-based etching, alkali etching offers a relatively safer and environmentally benign approach while increasing interlayer spacing, thereby enhancing ion accessibility and interfacial interaction. Structural and morphological analysis confirm successful composite formation, while X-ray photoelectron and Raman spectroscopies reveal strong interfacial coupling and improved electronic properties. Electrochemical measurements show that the composite delivers a high specific capacitance of 704 F g − 1 at 1 A g − 1 , significantly exceeding that of pristine [Co(BDC)DMF] n MOF (417 F g − 1 ), along with improved power capability. Electrochemical impedance spectroscopy analysis indicates reduced charge transfer resistance from 12.58 Ω (pristine) to 8.47 Ω (composite), confirming enhanced charge transport. Additionally, the [Co(BDC)DMF] n / partially etched MXene composite electrode exhibits 91% capacitance retention as compared to [Co(BDC)DMF] n , which shows 79% retention, after 5000 cycles. Moreover, assembled asymmetric supercapacitor achieved a 1.6 V operating window, an energy density of 22.7 W h kg − 1 and 114% of capacitance retention after 5000 cycles. The superior performance is attributed to the synergistic effect between redox-active Co 2+ - centres and the conductive MXene network, demonstrating a promising strategy for advanced supercapacitor applications.