High performance of activated carbons prepared from mangosteen (Garcinia mangostana) peels using the hydrothermal process

Abstract

Preparation of the activated carbon with electrochemical properties is essential in applying energy storage materials. Herein, a new method was reported to produce mangosteen peels activated carbons (MPACs). This strategy is based on the thermal aging of Mangosteen peels with hydrogen peroxide (H2O2) under hydrothermal conditions, followed by activation of KOH solid-state and carbonization under 800 °C for 1 hour. Various techniques such as the transmission electron microscope, field emission scanning electron microscope, X-ray diffraction, and X-ray photoelectron spectroscopy were used to confirm the successful preparation of MPACs. The findings indicated that well-structured micro/mesoporous structures make the prepared MPACs with well-defined amorphous shapes. After optimizing KOH as an activator with a different mass ratio, we found that the prepared MPAC-1 (1:1 mass ratio) holds an excellent electrochemical performance with a specific capacitance of 274.5 F/g at 0.5 A/g and a maximum capacitance retention rate of 94.5% after 10.000 cycles. More importantly, the symmetric device exhibits a high specific capacitance of 44.6 F/g at 1 A/g in 6 M KOH aqueous solution and demonstrated high specific energy of 12.14 Wh/kg specific power of 349.6 W/kg. The high electrochemical performance of MPACs was attributed to their large surface area (1078.92 m2/g) which shortens the ion diffusion paths and rapid migration of electrons. Our experimental results demonstrated that due to the simplicity of this newly introduced method and cost-effectiveness, MPACs have promising future applications in green energy production.