A review on copper current collector used for lithium metal batteries: Challenges and strategies

Abstract

Lithium (Li) metal anodes have become research hotspots due to their high theoretical specific capacity (3860 mAhg−1) and lowest REDOX potential (−3.04 V, based on the standard hydrogen electrode). When the Li metal is deposited/stripped directly on the current collector (i.e., anode-free Li metal batteries (AFLMBs)), the energy density increases compared with the graphite anodes. However, the extremely high reactivity of Li metal leads to the consumption of a large amount of inactive Li during the plating and stripping process, the growth of Li dendrites, and the formation of an unstable solid-electrolyte interface (SEI) film. Copper (Cu) was usually applied as the current collector in AFLMBs, playing a key role in Li nucleation/growth and lithium-ion flux distribution. However, the commonly used commercial Cu foil cannot meet the work needs of AFLMBs. Therefore, the modification of the Cu-based current collectors to reduce local current density, inhibit dendrite growth, and improve Coulombic efficiency (CE) has been widely studied and reported. Here, methods for modifying Cu-based current collectors are systematically summarized to guide the rational design of these modifications. Additionally, insights into the key challenges and future directions of the Cu used for Li metal anodes are presented.