Preparation of investigated carbon derived from pistachio shells for supercapacitor applications

This study investigates the preparation and characterization of activated carbon (AC) derived from pistachio shells for use as electrode material in supercapacitor applications. Pistachio shells, which are abundant and low-cost biomass waste, were utilized as a sustainable carbon precursor. This activated carbon is carbonized at 400℃ in a muffle furnace and activated using potassium hydroxide (KOH) at different mass ratios of activated carbon to KOH which 1:1 (AC-1), 1:2 (AC-2) and 1:3 (AC-3) and left for 24 hours. The activated carbon exhibited a high carbon yield of 93.2% and an ash content of less than 1%, indicating excellent carbon retention and purity. The electrochemical performance of the samples was evaluated in terms of capacitance, specific capacitance and energy density. AC-2 demonstrated the highest capacitance of 44 F, followed by AC-1 with 37 F, and AC-3 with 25 F. The specific capacitance values were found to be 1760 F/g for AC-2, 1480 F/g for AC- 1, and 1000 F/g for AC-3. In terms of energy density, AC-1 recorded the highest value at 8.2 Wh/kg, followed by AC-3 at 5.6 Wh/kg and AC-2 at 0.6 Wh/kg. Despite AC-1 achieving the highest energy density, AC-2 exhibited superior overall electrochemical performance due to its highest capacitance and specific capacitance, making it the most promising electrode material among all the samples. These findings highlight the potential of pistachio shell derived activated carbon as a high performance, eco-friendly, and cost-effective material for energy storage applications.