Benchmarking the Degradation Behavior of Aluminum Foil Anodes for Lithium‐Ion Batteries

Abstract Aluminum is an attractive candidate for replacing graphite anodes in lithium‐ion batteries because of its high specific capacity and the potential direct use as foil. However, achieving reversible reaction aluminum challenging due to volume changes, SEI formation, sluggish ion transport. Although prior work has investigated electrochemical transformation behavior aluminum, effects key variables, including areal per cycle alloy composition, are not well understood. Here, we carry out comprehensive testing benchmark performance two different foils (99.999 % Al 8111). We find that constant thickness, both foil compositions exhibit a power‐law dependence life on lithiated cycle, revealing degradation significantly more rapid at higher capacities. This interpreted “electrochemical fatigue” mechanism, analogy mechanical fatigue. Additionally, composition was found strongly affect Coulombic efficiency (CE), with high‐purity exhibiting initial CE but reduced long‐term stability. Finally, operando optical microscopy revealed spatiotemporal mechanisms amongst materials. improved understanding paves way efforts engineer aluminum‐based enhanced