Graphite/MWCNT Nanocomposite: A Novel Paint Electrode for Energy Storage Devices

The study demonstrates the development of graphite/MWCNT nanocomposite electrodes for supercapacitors. The composite has been developed as a conducting carbon paint, wherein the properties have been studied by varying the MWCNT content. The optimized electrode (with 1 wt % MWCNT in graphite) exhibits a specific capacitance of 221.66 F/g @ 0.5 A/g in a three-electrode setup. The electrode was analyzed in solid-state and aqueous prototype supercapacitor devices. The solid-state device achieved an energy density of 24.5 Wh/kg @ 523.6 W/kg power density, with 91% capacity retention and 106.25% Coulombic efficiency after 7500 charge–discharge cycles. Expanding the scope of our investigation, nanocomposite paint was further tested as an electrode for the Zn–Br redox flow battery wherein the samples exhibited well-defined peaks for the 2Br–/Br2 redox reaction. A sample with 1% MWCNTs showed not only a 70% hike in current density as compared to graphite electrodes but also lower peak separation values predicting a more reversible and kinetically favored bromine redox reaction, thus projecting it as an efficient electrode for RFB. Our efforts establish the groundwork for future high-performance energy storage devices by connecting fundamental research with real-world applications.