Enhanced electrochemical performance of NiCoMn MOFs with Ag-citrate/SWCNT nanocomposites for high-energy supercapacitors

Abstract

Supercapacitors are advanced energy storage devices offering high power density, rapid charge/discharge cycles, and excellent cycle life, effectively bridging the gap between conventional capacitors and batteries. Herein we report one step hydrothermal synthesis of a novel composite material i.e. NiCoMn MOFs with pre-amalgamated Ag citrate and functionalized single-walled carbon nanotubes (f-SWCNTs) in a 3:1 weight ratio at varying compositions for supercapacitor applications. The morphological and chemical characterization of pristine and synthetic materials' composites were done through XRD, SEM, and FTIR techniques. The best performance during electrochemical analysis was shown by electrode containing equal weight of NiCoMn MOFs and the Ag citrate/f-SWCNTs composite, with a discharge time of 621 s and a specific capacitance of 730 F/g at 0.5 A/g, nearly doubling the 370 F/g value for pristine MOFs. The electrode also exhibited lowest resistance values and attained energy and power densities of 25.34 Wh/kg and 146.9 W/kg, respectively, with 100 % Coulombic efficiency and 115 % capacitance retention for over 4000 cycles. This excellent nature can be attributed to the fact that the electrical properties of Ag citrate/f-SWCNTs composite improved the MOFs as a whole, by providing the conductive channels for ion transportation. The present work can effectively contribute to the development of new and durable supercapacitor materials adding to the advancement of energy storage materials.