Dual mutual-philic interfaces enabled by a facile Li-Si anode for scalable and long-cycle-life all-solid-state batteries

Scalable and long-cycle-life all-solid-state lithium batteries (ASSLBs) are inevitable, but still remain two key challenges of electrode-electrolyte and current collector-electrode interfaces. Here, we propose dual mutual-philic interfaces enabled by a facile Li-Si anode for scalable and long-cycle-life ASSLBs, which simultaneously address both bottlenecks. As a proof-of-concept, the optimized Li-30 wt.% Si alloy (Li-30Si) anode is selected to match state-of-the-art Li₆P₅SCl solid-state electrolyte and commercial Cu current collector, achieving dual mutual-philic interfaces in ASSLBs. The Li-30Si/Li₆P₅SCl electrode-electrolyte interface exhibits a dense and conformal contact, meanwhile the Li-30Si/Cu current collector-electrode interface shows an enhanced interfacial affinity. X-ray photoelectron spectroscopy analysis confirms the effective suppression of Li₆P₅SCl reductive byproducts including Li₃P, Li₂S and lithium polysulfides (Li₂S_n); and electrochemical measurements demonstrate a significantly increased critical current density. Greatly improved electrochemical and mechanical stabilities at dual mutual-philic interfaces are confirmed. When paired with an LiNi_0.83Co_0.11Mn_0.06O₂ cathode, the Swagelok-type ASSLB exhibits a high-capacity retention of 87.5% over 400 cycles. More encouragingly, a 0.1 Ah pouch cell achieves 78.8% capacity retention after 300 cycles, highlighting its promise for practical scale-up. The dual mutual-philic interfaces provide a sustainable way to advance scalable and long-cycle-life ASSLBs.