Synergetic interplay of a nitrogen- and sulfur-rich copper bi-linker 2D cubic-layered MOF composite with MXene for improved hybrid supercapacitor application†

To combine the properties of batteries and capacitors in a single hybrid device, metal–organic frameworks have emerged as promising materials. In this study, by incorporation of a heteroatom (N, O and S)-based bi-linker, a novel copper-based two-dimensional metal–organic framework (Cu-SIP-MOF), derived from 5-sulfoisophathalic acid monosodium salt (SIP sodium salt) and 4,4-bipyridine was synthesized and characterized using different techniques. The conductivity of the extended 2D MOF was attributed to π-d orbital contribution, which was further enhanced by fabricating its composite with MXene. The synthesized MOFs and its composites were electrochemically evaluated using different electroanalytical techniques such as cyclic voltammetry, galvanostatic charge–discharge and electrochemical impedance spectroscopy via three-electrode assembly. The composites of Cu-SIP-MOF with MXene (CM-200) in a 1 : 2 ratio possessed the highest specific capacity of 683.69 C g⁻¹, highlighting the potential for their practical implementation in asymmetric hybrid devices. The material demonstrated an energy density and a power density of 62 W h kg⁻¹ and 2330.4 W kg⁻¹, respectively. It also expressed 98.3% coulombic efficiency after 5000 galvanic charge–discharge cycles. The significant values of specific capacity, energy density and power density of CM-200 make it a promising electrode material for a futuristic hybrid device.