High-Stability Lithium Metal Batteries Enabled by AZO-Modified Separators.

The commercialization of lithium metal batteries is hindered by critical challenges such as uncontrollable lithium dendrite growth and interfacial instability. Constructing functional nanocoatings on separator surfaces represents an effective strategy to address these issues. In this study, a uniform aluminum-doped zinc oxide (AZO) modification layer was deposited on the separator via magnetron sputtering to enhance the electrochemical performance and safety of lithium metal batteries. The AZO layer combines the functions of a physical barrier and an interfacial regulator. On one hand, it effectively suppresses lithium dendrite penetration through the separator. On the other hand, its surface properties facilitate uniform lithium-ion transport and reduce the deposition overpotential. Experimental results demonstrate that the symmetric cells employing AZO-modified separators exhibit significantly reduced and stable lithium deposition overpotentials. In full cells assembled with a nickel cobalt aluminum (NCA) cathode, the system demonstrates higher specific capacity and notably extended cycle life compared to cells using unmodified polyethylene (PE) separators. This work proposes a practical strategy based on AZO-modified separators, offering a promising pathway toward the development of next-generation lithium metal batteries with high energy density and improved safety.