Effects of E-Beam Irradiation on the Chemical, Physical, and Electrochemical Properties of Activated Carbons for Electric Double-Layer Capacitors

Activated carbons (ACs) were modified via e-beam irradiation at various doses for use as an electrode material in electric double-layer capacitors (EDLCs). The chemical compositions of the AC surfaces were largely unchanged by the e-beam irradiation. The ACs treated with the e-beam at radiation doses of 200 kGy exhibited higher nanocrystallinity than the untreated ACs. The specific surface areas and pore volumes of the e-beam irradiated ACs were also higher than those of the untreated ACs. These results were attributed to the transformation and degradation of the nanocrystallinity of the AC surfaces due to the e-beam irradiation. The specific capacitance of the ACs treated with the e-beam at radiation doses of 200 kGy increased by 24% compared with the untreated ACs, and the charge transfer resistance of the ACs was decreased by the e-beam irradiation. The enhancement of the electrochemical properties of the e-beam irradiated ACs can be attributed to an increase in their specific surface area and surface crystallinity.