Energy storage capabilities of spent pot lining and ZnO composite for supercapacitor applications

The quest for sustainable and efficient energy storage materials has driven the development of novel electrode materials. Here, we report on chemically treated activated spent pot lining (SPL) combined with zinc oxide (ZnO) to create composite electrodes with enhanced performance for supercapacitor applications. Comprehensive characterization revealed the graphitic structure and high surface area (308 m²/g) of the treated SPL, while the addition of ZnO introduced synergistic charge storage through electrical double-layer capacitance and pseudo capacitance. Electrochemical evaluation in 2 M H 2 SO 4 showed that the SPL-ZnO (3:1) composite achieved exceptional energy storage metrics, including a specific capacitance of 322.3 F/g at 1 A/g, an energy density of 64.5 Wh/kg, and a power density of 780.8 W/kg. Notably, this composite retained 97.4 % of its capacitance after 5000 cycles, indicating its long-term stability. These results demonstrate the potential of upcycled SPL as a sustainable material for advanced supercapacitor technologies, addressing critical challenges in renewable energy storage. • Environmentally friendly spent pot lining (SPL) was produced and KOH-activated. • SPL/ZnO composite electrodes were formulated for supercapacitor applications. • SPL-ZnO (3:1) electrode showed maximum energy of 64.5 Wh/kg and power of 780.8 W/kg. • Maximum capacitance retention of 98.4 % was achieved by SPL-ZnO (3:1) composite.