Waste-Derived Activated Carbon from Primary Battery Rods for Sodium-Ion Battery Anodes

The growing accumulation of primary battery waste presents both environmental challenges and opportunities for resource recovery. In this study, carbon rods from primary battery waste were successfully converted into activated carbon and applied as an anode material for sodium-ion batteries. Chemical activation using KOH followed by thermal treatment was employed to enhance structural and surface properties.SEM analysis revealed a significant reduction in particle size after activation, indicating increased surface area, while EDX confirmed a substantial increase in oxygen-containing functional groups. FTIR results further identified O–H, C=O, and C–O groups, which contribute to improved electrolyte wettability and ion accessibility.Electrochemical evaluation revealed that the activated carbon–graphite composite exhibited the highest discharge capacity of 164.38 mAh g⁻¹, meanwhile carbon (33.61 mAh g⁻¹) and activated carbon (90.29 mAh g⁻¹). This higher performance is ascribed to a synergistic interaction between activated carbon's porous structure, which supplies plentiful active sites, and graphite's improved electrical conductivity, which allows for efficient electron transport. Cyclic voltammetry analysis confirms that sodium storage is mostly dominated by surface-controlled capacitive mechanisms, which is consistent with the disordered carbon structure discovered through XRD analysis.These findings reveal a sustainable and cost-effective technique for converting hazardous primary battery trash into usable activated carbon materials with promising anode properties for sodium-ion batteries