Advancing Anode-Less Lithium Metal Batteries: ZnF2 Modification and In-Situ Structural Regulation for Enhanced Performance

Abstract

Lithium metal anode tends to form non-uniform Li⁺ deposition and cause dendrite growth during cycling. Meanwhile, the deposition and dissolution of Li⁺ and lithium metal often result in the continuous formation and breakdown of the SEI. Additionally, the use of thick lithium metal often results in an excessive inventory of lithium, which diminishes the energy advantage of lithium metal. It is challenging to fabricate thin lithium foils due to its low mechanical strength. To address these issues, we employ an in-situ structural regulation strategy to prepare high-performance lithium metal batteries. In this paper, the mechanical strength of the LiF@LiZn10/Li foil is significantly enhanced, allowing it to be thinned down to a thickness of 5 μm, accompanied by great air stability. The in-situ formation of LiZn alloys improves the Li⁺ deposition behavior. Furthermore, we have demonstrated the participation of LiF particles in the in-situ formation of the SEI, which facilitates Li⁺ transport kinetics. The LiF@LiZn10/Li electrode demonstrates significantly enhanced cycling performance by synergistically improving Li⁺ deposition behavior and optimizing the SEI layer in situ. The LiF@LiZn10/Li foil electrode exhibits a long cycle life of over 1300 hours at 1 mA cm^-2 and 1 mA h cm^-2. When coupled with a commercial LiFePO₄ cathode (3.3 mA h cm^-2), LiFePO₄||LiF@LiZn10/Li cell exhibited approximately triple the cycling life compared to cells with LMBs. This work provides a novel strategy to optimize LMAs for next-generation LMBs.