Pyrolytic cyanobacteria derived activated carbon as high performance electrode in symmetric supercapacitor

•Demonstrate that cyanobacteria is promising precursor for supercapacitor electrodes.•The activated carbon was obtained by chemical pyrolysis.•The activated carbon had a large surface area of 2184 m2 g−1.•The activated carbon exhibited a high specific capacitance of 271 F g−1 and excellent stability.

Cyanobacteria, as a renewable source of carbon, was used to prepare activated carbon electrodes in supercapacitors. The activation includes a pre-carbonization at 400 °C followed by KOH heat treatment at 800 °C, leading to efficient and high degree of graphitization. The activated carbon electrode consisted primarily of carbon and oxygen, and possessed a large specific surface area of 2184 m2 g−1, with pore size centered at 27 nm. In 6 mol L−1 KOH electrolyte, the electrode exhibited superior specific capacitance of 271 F g−1 and 222 F g−1 at a charge/discharge current density of 0.1 A g−1 and 5.0 A g−1, respectively. The results demonstrated that the activated carbon derived from cyanobacteria can serve as promising electrode material for electrical double-layer capacitors.

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