1 Introduction Electric Double Layer Capacitors (EDLCs) store energy simply via the formation of an electric double-layer at the electrode/electrolyte interface (capacitive storage). Since no faradaic (redox) reaction or chemical modification of the electrode occurs, EDLCs can display excellent cycle life (up to millions of cycles), fast charge/discharge rates, and subsequently very high-power density (>10 kW kg−1) [1, 2].