Ultrastable Anode/Electrolyte Interface in Solid-State Lithium-Metal Batteries Using LiCu x Nanowire Network Host.

High interfacial resistance and uncontrollable lithium (Li) dendrite are major challenges in solid-state Li-metal batteries (SSLMBs), as they lead to premature short-circuiting and failure of SSLMBs. Here, we report the synthesis of a composite anode comprising a three-dimensional LiCu _x nanowire network host infiltrated with Li (Li* anode) with low interfacial impedance and superior electrochemical performance. The Li* anode is fabricated by dissolving Cu foil into molten Li followed by solidification. The Li* anode exhibits good wettability with Li _6.4 La ₃ Zr _1.4 Ta _0.6 O ₁₂ (LLZTO) and high mechanical strength, rendering low Li*/LLZTO interfacial impedance, homogeneous deposition of Li, and suppression of Li dendrites. Consequently, the Li* anode-based symmetric cells and full cells with LiNi _0.88 Co _0.1 Al _0.02 O ₂ (NCA), LiFePO ₄ (LFP), and FeF ₂ cathodes deliver remarkable electrochemical performance. Specifically, the Li*/LLZTO/Li* symmetrical cell achieves a remarkably long cycle lifetime of 10 000 h with 0.1 mA·cm ^-2 ; the Li*/LLZTO/NCA full cell maintains capacity retention of 73.4% after 500 cycles at 0.5C; and all-solid-state Li*/LLZTO/FeF ₂ full cell achieves a reversible capacity of 147 mAh·g ^-1 after 500 cycles at 100 mA·g ^-1 . This work demonstrates potential design tactics for an ultrastable Li*/garnet interface to enable high-performance SSLMBs.