Tailored MnMoO4-Nb2C architecture as electrode material for supercapattery application

To meet the increasing energy demand, it is essential to develop efficient energy storage devices which enable the storage of surplus energy from renewable energy sources. While batteries are renowned for their high energy density and reliability, they often struggle with delivering rapid power due to limited power density. Conversely, supercapacitors excel with their exceptional power density, but they are constrained by their limited energy storage capability. To address this challenge, the supercapattery was introduced, uniting the strengths of rechargeable batteries and supercapacitors with battery-type and capacitor-type electrodes in a single device. This study investigates the behaviour of Nb 2 C MXene combined with the transition metal oxide MnMoO 4 to improve overall electrochemical performance of the system. The specific capacity of 239 C/g and 232 C/g at 1 A/g current density is observed for bare MnMoO 4 and Nb 2 C. Among the different composites, MnMoO 4 -Nb 2 C 2:1 achieves the outstanding specific capacity of 532 C/g at 1 A/g. The full cell device in combination with orange peel carbon provides the total capacity of 105 C/g at 1 A/g with energy and power density of 22 Wh/kg and 754 W/kg, respectively. Also, the device retains its initial specific capacity of 78% after 12,000 cycles with coulombic efficiency of ⁓100%. This electrode material offers considerable potential for supercapattery applications, delivering an outstanding balance of high energy and power density to optimize overall performance.