Optimization of Cu-based current collectors for Li-metal and anode-free Li-metal batteries: Can we achieve both stability and practicality?

초록

Li-metal batteries (LMBs) and anode-free Li-metal batteries (AFLMBs) are next-generation energy storage systems that offer high energy densities and excellent performance. Strategies for stabilizing and engineering the individual components in these systems are critical for their practical application. Cu current collectors (CCs) are widely used in commercial Li-ion batteries (LIBs) because of their high electrical conductivity and electrochemical stability. In LMBs and AFLMBs, Cu CCs serve as deposition sites for metallic Li during charging. However, Cu exhibits inherently low affinity for Li, known as lithiophobicity. This results in high nucleation overpotentials and nonuniform Li deposition, which ultimately limits the stability and cycle life of the battery. Therefore, the modification of Cu CCs is essential to address these challenges. This review systematically analyzes the requirements for modified Cu CCs in LMBs and AFLMBs, with a focus on recent advancements in surface modification and structural engineering. The effects of modified Cu CCs on battery performance are also discussed. Finally, the review outlines future directions toward the commercialization of high-energy-density LMBs and AFLMBs. Especially, this review evaluates Cu CC modification strategies through a stability and practicability lens by distinguishing configuration dependent requirements in LMBs versus AFLMBs and emphasizing cell level considerations and structure function descriptors. Collective insights from this review will help overcome the current limitations of LMBs and AFLMBs and support the development of efficient and reliable energy storage systems.

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