A review on current collector coating methods for next-generation batteries

The current collector (CC) collects electrons from electrode materials and transports them to the external circuit. Although the CC is an essential part of battery configuration, it has not received considerable attention because there are "champion materials" such as Al and Cu foils in the commercial market. However, in accordance with the diversification of battery systems and the development of high energy density lithium-ion batteries, conventional CCs cannot address emerging issues. In particular, for alkali-metal-based or anode-free systems, a safety issue occurs due to unstable metal plating on CC. Here, we examined the roles of CCs in battery systems and categorized the problems occurring in CCs. Moreover, we especially focused on the coating methods among CC modification because surface coating is facile and has a wide scope of application. We paid attention to the latest research progress (2016-) and summarized the cases of coating materials and methods on various types of substrates and their applications to state-of-the-art battery systems. To the best of our knowledge, this is the first review to systematically organize CC coating methods, which would be a good opportunity to understand the current research flow.