Interfacial Engineering of a Lithiophilic Li–Ag–Zn Ternary Alloy Anode for Long-Life Garnet-Based Solid-State Batteries

Li6.4La₃Zr1.4Ta0.6O₁₂ (LLZTO)-based solid-state lithium metal batteries (SSLMBs) are regarded as promising candidates for next-generation energy storage, owing to their nonflammability and high energy density. Nevertheless, practical application is hindered by poor interfacial contact and structural degradation at the Li/LLZTO interface during stripping processes, which induces lithium dendrite growth and battery failure. In this study, a ternary Li-Ag-Zn alloy anode (LAZ10) is in-situ constructed by introducing 10% Ag and Zn into molten lithium, which markedly improves interfacial adhesion and facilitates Li⁺ transport. As a result, LAZ10/LLZTO/LAZ10 symmetric cells demonstrate ultralow interfacial resistance of 4 Ω·cm², high critical current density (CCD) of 1.6 mA cm⁻², and long cycle life of 2800 h at 0.3 mA cm⁻². Furthermore, full cells LAZ10/LLZTO/LiFePO4 exhibit outstanding electrochemical performance. This work provides an effective interfacial design strategy for developing high-performance, dendrite-free SSLMBs.