Empowering all-solid-state Li-ion batteries with self-stabilizing Sn-based anodes

Abstract

All-solid-state Li-ion batteries (ASSLIBs) are promising but face several challenges, especially regarding Li-metal anodes prone to dendrite formation and Si-based anodes with limited performance. To address this issue, we propose a self-stabilizing Sn-based anode. While Sn anodes suffer from agglomeration during cycling, transition metal-Sn anodes, specifically FeSn₂ anodes, self-stabilize during cycling by exhibiting uniformity and densification without cycling-induced agglomeration, owing to their unique electrochemical-cycling-induced size reduction and distinctive mechanical properties. A full cell with an FeSn₂ anode, a LiNi_0.6Co_0.2Mn_0.2O₂ cathode, and a Li₆PS₅Cl solid electrolyte exhibits highly reversible areal capacity (15.54 mAh cm⁻² at 100 mg cm⁻² cathode loading), excellent rate capability (74.5%/83.2% retention over 1,000 cycles at 10/20 C), and exceptional energy density at high current densities. The self-stabilizing FeSn₂ anodes offer high energy density, compatibility with solid electrolytes, safety, wide operating temperature range, cost effectiveness, and scalability, thereby accelerating the realization of superior ASSLIBs.