From Stability Strategies to Practical Implementation: Recent Progress and Prospects on Ultrathin Lithium Metal Anodes

The relentless pursuit of high-energy-density storage systems (>500 Wh kg–1) has established lithium metal batteries as a core technology, owing to their unparalleled theoretical capacity and low electrochemical potential. Recently, growing evidence has revealed that anode thickness compromises both efficiency and safety. Thus, ultrathin lithium metal anodes (LMAs, ≤20 μm) have emerged as a breakthrough strategy, maximizing energy density while overcoming the limitations of thick electrodes. However, there is still a demand for diverse strategies to produce thin and stable LMAs, and systematic reviews on this topic remain scarce. Considering these, we critically summarize the opportunities and challenges of ultrathin LMAs, with a focus on recent advances in stability and fabrication strategies to provide a comprehensive perspective. Our goal is to go beyond the limitations of existing summaries by bridging concepts across materials chemistry, interface engineering, and processing techniques, thereby accelerating the practical implementation of ultrathin LMAs.