A low cost Chinese cabbage derived porous carbon for high-performance green supercapacitor

Currently, the design of efficient multifunctional materials for supercapacitors has become imperative in the field of energy storage and conversion. Porous carbon materials derived from biomass have been widely regarded as the promising electrode materials for supercapacitors. Herein, we have prepared porous carbon materials with Chinese cabbage as the biomass precursor by a facile pyrolysis and potassium hydroxide activation process. Based on the characterisation, Chinese cabbage–derived activated carbon (CAC-3) with a hierarchical micro-/meso-/macroporous structure indicates Brunauer–Emmet–Teller surface area of ∼953 m2/g and an average pore size of 2.27 nm. CAC-3 indicates outstanding capacitive performance of 760 F/g at 1 A/g and good rate capability as well as superior cycling stability 95.45% of initial specific capacitance after 10 000 cycles. Moreover, the supercapacitor delivers a high specific capacitance of 266.7 F/g at 1 A/g and 78.74% of the capacitance retention at 20 A/g as well as a high energy density of 53.34 Wh/kg at power density of 1200 W/kg. This study provides new insight for the exploration of novel electrode materials with multifunctional structures for green supercapacitor.