Investigation on activated carbon derived from biomass Butnea monosperma and its application as a high performance supercapacitor electrode

In the present work, Butnea monsperma flower pollens (BMPs) were used to synthesize high surface area activated carbons (ACs). ACs were prepared employing one-step thermal activation process, by varying the ZnCl₂ impregnation ratio. Optimization was done to ensure suitable porosity parameters and better electrochemical performance. Optimization succeeded in achievement of large values of total pore volume (~0.77 cm³ g⁻¹) and specific surface area (~1422 m² g⁻¹). Electrochemical characteristics of optimized AC were compared in aqueous and ionic liquid based electrolyte. The value of capacitance of AC electrode was observed to be large ~130 F g⁻¹) in aqueous electrolyte. Large magnitudes of specific energy (~42 Wh kg⁻¹) and specific power (~19 kW kg⁻¹) were observed in ionic liquid based electrolyte. Further, it has been observed that AC provided capacitance retention of more than ~99% (for more than 10,000 cycles). Synthesized AC is thus believed, profitable for energy storage devices.