The preparation of 3D network pore structure activated carbon as an electrode material for supercapacitors with long-term cycle stability

Abstract

The high performance bio-based activated carbon (BAC) was prepared via a novel combination of chemical and physical activation processes using coconut shells as a precursor. The as-obtained BAC exhibited a three-dimensional (3D) network pore structure, high specific surface area (3242.05 m² g⁻¹), unobstructed and interconnected pores, and large pore volume (1.919 cm³ g⁻¹). The BAC exhibited a high specific capacitance of 337 F g⁻¹ (202 F cm⁻³) and retained a specific capacitance of 331 F g⁻¹ (190 F cm⁻³) after 10 000 cycles (98% capacitance reservation) at a current density of 0.5 A g⁻¹ in a 6 M KOH electrolyte. AC-W had a gravimetric capacitance value of 240 F g⁻¹ and a volumetric capacitance value of 120 F cm⁻³ in 1 M TEA BF₄/AN. The BAC shows ideal properties as electrode material and also exhibits long-term cycle stability, low capacitance loss rate and high capacitance as an electrode material in aqueous and organic electrolytes. These results are expected to develop efficient, environmentally friendly and low-cost supercapacitors, as well as to promote their application in future electric vehicles, mobile phones and power electronics.