A novel capacitor electrode auxiliary, deoxyribonucleic acid (DNA), is applied to an electric double layer capacitor (EDLC) containing an aqueous 3.5M NaBr electrolyte. The present electrode is composed of activated carbon (95wt.%) and DNA (2.5wt.%) with polytetrafluoroethylene (PTFE) as a binder (2.5wt.%). An EDLC cell with the DNA-loading electrodes exhibits improved rate capability and discharge capacitance. An EDLC cell with DNA-free electrodes cannot discharge above a current density of 3000mAg−1 (of the electrode), while a cell with the DNA-loading electrodes can work at least up to 6000mAg−1. Moreover, an open-circuit potential (OCP) of the DNA-loading electrode sifts negatively with ca. 0.2V from an OCP of the corresponding electrode without DNA. It is noteworthy that a small amount of DNA loading (2.5wt.%) to the activated carbon electrode not only improves the rate capability but also adjusts the working potential of the electrode to a more stable region.