Deposition of Corrosion Preventing Coatings for Dual-Ion Batteries

Commercial lithium ion batteries (LIB) are built with liquid electrolytes containing organic carbonates and lithium hexafluorophosphate (LiPF6). The flammability of these carbonates implies safety risks which could be avoided by replacing the electrolyte mixtures by ionic liquids (ILs), e.g. based on anions like bis(trifluoromethylsulfonyl)imide (TFSI). Additionally, LiPF6 (which also tends to thermal decomposition) can be substituted by appropriate conducting salts, e.g. LiTFSI. Since these components show negligible vapor pressure and high thermal stability, the danger of thermal runaway is minimized, but some problems are still to be solved. In this context, anodic dissolution of the aluminum current collector is a very important issue. To overcome this drawback, innovative protection coatings are deposited on aluminum foils by magnetron sputtering