Enhancing the performance of carbon electrodes in supercapacitors through medium-temperature fluoroalkylation

Medium-temperature fuoroalkylation of microporous activated carbons (ACs) with 1,1,1,2-tetrafuoroethane is presented. Supercapacitor (SC) electrodes based on the fuoroalkylated ACs showed enhanced specifc capacitance and high specific energy in electrolytes, either aqueous potassium hydroxide solution or tetraethylammonium tetrafuoroborate-acetonitrile solution. We found the largest increase in the specific capacitance, up to 89 F g–1, and in the specifc energy, up to 7.5 Wh kg–1, at the voltage of 1.5 V. The specific capacitance of the SC electrode based on the sample prepared at 350 °C increases
by a factor of ~2–3× for certain scan rates in the organic electrolyte. The fuoroalkylated ACs have good electrochemical stability in the tested model systems. We associate the registered enhanced SC parameters with an increase in the total fuorine content and high specifc surface areas of the carbon electrode materials. The surface “isolated fuorine” formed during fuoroalkylation at 300–400 °C ensures the production of improved electrode materials for SC applications. Fluoroalkylation is a simple and cost-efective method of improving the specifc capacitance of carbon-based SC electrodes.

Reproduced with permission. Copyright 2021, Springer Nature

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