Modification of Cu current collectors for lithium metal batteries – A review

The energy density of lithium metal batteries (LMBs) could be much higher than that of current graphite anode-based LIBs. When a metallic current collector is used for plating/de-plating of lithium (i.e., anode-free lithium metal batteries (AFLMBs)) energy density could be higher by about 70%. However, LMBs suffer from dendritic lithium growth and formation of an unstable solid-electrolyte interface, which requires careful control to improve the cycling performance and the overall safety. The current collector (CC), typically Cu, plays an important role in lithium nucleation/growth, local current density and Li-ion flux distribution. However, the commonly used planar Cu CC does not work satisfactorily, and as such, modifications of Cu CC, for decreasing the local current density, suppressing the lithium dendrite growth, and improving the Coulombic efficiency (CE), have been widely investigated and reported in the literature. This review systematically summarizes the modification methods for Cu CCs and serves as a guide for rational design of modified Cu CCs with tailored structures and properties. Furthermore, misrepresentation and misinterpretation of data, which are often observed in the literature on this topic, are critically discussed and insights into the key challenges and future directions on this topic are presented.