Volumetric capacitance of compressed activated microwave-expanded graphite oxide (a-MEGO) electrodes

Abstract

Volumetric capacitance is an important parameter for device applications. By simply compressing activated microwave-expanded graphite oxide (a-MEGO)-based electrode material, a volumetric capacitance of up to 110 F/cm(3) (3.5V maximum voltage) was achieved, when measured in a two-electrode cell supercapacitor configuration in an organic electrolyte. Nitrogen adsorption showed that the mesopores of a-MEGO (similar to 4 nm) collapsed due to the compression, and more micropores (1-2 nm) contributed to the energy storage in the compressed electrodes compared to uncompressed electrodes. This change in pore structure resulted in a higher effective series resistance and thus reduced power density in the compressed samples.