An Investigation on Activated Carbons Used for Electrodes Materials inHigh-Power Electric Double-Layer Capacitors

摘要

Abstract: High-power electric double-layer capacitors (EDLCs) were manufactured in different electrolytesystems with the porous carbon as the electrode materials. The electrochemical behavior of various activated carbons(ACs) in aqueous and in organic electrolyte systems has been investigated for EDLCs by the way of EIS, constantcurrent charge/discharge and FT-IR. The results show that the sample AC-6 is a qualified carbon material for EDLCswith a specific capacitance as high as 117 F/g in KOH system. It is important to note that the soakage of the porouscarbon materials in the electrolyte was the main factor. Its surface functional groups play a leverage role in thewetting properties of the interface between solid and liquid phases.Six kinds of organic electrolyte samples were selected to compare their properties. The capacity, theelectrochemical impedance and the cycle life were mainly investigated. It was found that the Et4NBF4/PC systemwas the best choice for the organic system EDLCs due to decomposition of LiPF6/PC and LiPF6/(EC＋PC) .