CMK-5-Based High Energy Density Electrical Double Layer Capacitor for AC Line Filtering

Compact electrical double layer capacitors (EDLCs) can be applied to the AC line filtering process and potentially replace conventional bulky aluminum electrolytic capacitors. However, to realize the AC line filtering application, the energy density of the EDLCs needs to be significantly increased while high power density is maintained. In this work, we demonstrate the EDLCs fabricated with ordered mesoporous carbon, CMK-5, and small amounts of single walled carbon nanotubes (SWNTs), which exhibit the highest areal energy density among various EDLCs reported so far and power performance sufficient for AC line filtering. High energy density of CMK-5/SWNT EDLCs can be attributed to high capacitance arising from the bimodal mesoporosity of CMK-5 and high operation voltage owing to the pores compatible with ion sizes in organic electrolytes. High power density is ascribed to the high electrical conductivity and straight ordered pore structure of CMK-5, enabling facile ion movements. Therefore, the carbon pore structure is one of the critical factors to be controlled for the enhancement of the overall performance of EDLCs for AC line filtering. Our demonstration would greatly contribute to the scientific and technological advancement of AC line filtering EDLCs.