Distillers dried grains with soluble (DDGS) bio-char based activated carbon for supercapacitors with organic electrolyte tetraethylammonium tetrafluoroborate

•DDGS is a sustainable material from corn ethanol industry.•Half graphitized activated carbon was obtained through chemical activation.•High specific capacitance of 150 F g−1 was obtained in organic electrolyte system.

Distillers dried grains with soluble (DDGS) is the main byproduct of the corn-based ethanol industry. DDGS could be used as a renewable energy source through pyrolysis or gasification. However, biochar, the main byproduct, does not have commercial value. DDGS biochar can be utilized in supercapacitors when it is converted to activated carbon. Activated carbon samples were prepared at 950 and 1050 °C with KOH/ bio-char loading of 0.075 mol g−1. Symmetrical supercapacitors were assembled using the activated carbon samples as electrode materials and 1 mol L−1 tetraethylammonium tetrafluoroborate (TEA BF4) in acetonitrile as the electrolyte. The 950 °C activated carbon presented higher specific capacitance than the 1050 °C sample (150 F g−1 verse 70 F g−1). The capacitance was stable after 1000 cycles. More importantly, the capacitive performances of these activated carbons are comparable to ordered mesoporous carbons and commercial graphene. Thus, we highlight the success of preparing high performance supercapacitor electrode material from renewable biomass as well as the potential for generating advanced carbon materials from pyrolysis and gasification byproduct.

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