Interface Engineering of Aluminum Foil Anode for Solid-State Lithium-Ion Batteries under Extreme Conditions

Alloy foil anodes have garnered significant attention because of their compelling metallic characteristics and high specific capacities, while solid-state electrolytes present opportunities to enhance their reversibility. However, the interface and bulk degradation during cycling pose challenges for achieving low-pressure and high-performance solid-state batteries. In this study, we engineered a nonintrusive solid-state electrolyte rich in fluorine and boron and developed aluminum metal foils featuring a densely structured and highly lithiated interface, effectively suppressing interfacial contact loss and promoting the formation of a stable interfacial layer rich in fluorine and boron, helping to minimize fluctuations in Coulombic efficiency. With high areal cathode capacities (∼2.5 mAh cm–2), the low-pressure solid-state battery exhibited stable cycling performance for over 140 cycles, achieving an average Coulombic efficiency of 99.86%. Our findings provide a solid framework for designing durable electrolyte/anode interfaces in ambient-pressure, intrinsically safe alloy-foil-based solid-state batteries.