Preparation of activated carbon from willow leaves and evaluation in electric double-layer capacitors

•ACs were prepared by one-step pyrolysis of willow leaves with ZnCl2 activation.•AC-1-800 exhibits high specific surface area of 1031 m2 g−1.•The specific capacitances reaches 216 F g−1 at a current density of 0.1 A g−1.•The retention of specific capacitance is 97% after 1000 cycles at 2 A g−1.

In this paper, willow leaves were used to prepare activated carbons (ACs) by one-step pyrolysis with ZnCl2 activation. The as-prepared AC-1-800 exhibits porous structure with high specific surface area of 1031 m2 g−1 and a large pore volume of 0.66 cm3 g−1. As a supercapacitor electrode, it shows a good capacitive performance in 6 M of KOH aqueous electrolyte, such as the specific capacitance reaches 216 F g−1 at a current density of 0.1 A g−1 and the retention of specific capacitance is 97% after 1000 cycles at 2 A g−1.

Graphical abstractWillow leaves were used to prepare activated carbons (ACs) by one-step pyrolysis with ZnCl2 activation. AC-1-800 exhibits high specific surface areas of 1031 m2 g−1. The specific capacitances of ACs electrode reaches 216 F g−1 at a current density of 0.1 A g−1, and the retention of specific capacitance is 97% after 1000 cycles at 2 A g−1.Figure optionsDownload full-size imageDownload as PowerPoint slide