Development of Corrosion Protection Layers for Current Collectors in Dual-Ion Batteries

摘要

In novel dual-ion cells graphite intercalation compounds will be used for both electrodes. The consequent intercalation of both, cations and anions, in the respective electrodes enables voltage values above 5 V. Established liquid electrolytes do not resist these conditions. Therefore those are replaced by ionic liquids having a good electrochemical performance also at higher temperatures. Now the challenge is to overcome the corrosion of the aluminium current collector triggered by fluorinated anions like bis(trifluoromethylsulfonyl)imide (TFSI). Our approach to protect the metal against corrosion is the deposition of an only electronically conductive, defect free and mechanically as well as electrochemically stable layer. Different material compositions in the range of oxidic ceramics are tested, first of all doped semiconductors, e. g. alumina doped zinc oxide. The preparation is based on a sol-gel route combined with several wet-chemical coating methods, because these are easily adjustable to different substrate sizes. Cyclic voltammetry is used to investigate the electrochemical performance of the protection layers on aluminium substrates.