Processing of Al-doped ZnO protective thin films on aluminum current collectors for lithium ion batteries

In this work, aluminum current collectors for Li-ion batteries were coated with protection layers made of Al-doped ZnO (ZnO:Al) to prevent the corrosion of aluminum caused by bis(trifluoromethylsulfonyl)imide (TFSI−) at 5 V. These thin films of ~ 100 nm thickness were prepared with a facile and scalable sol-gel coating process with subsequent heat treatment by rapid thermal processing (RTP) at 500 °C. The ZnO:Al films exhibited the usual hexagonal phase, a homogeneous morphology and a sufficient electronic conductivity. In electrochemical testing, chronoamperometry demonstrated that the protection layer reduces the corrosion of the aluminum current collector 120 times compared with conventional unprotected aluminum.