Unlocking the High Capacity and Stability of Aluminum Anodes for Lithium-Ion Batteries through Strategic Thermal Control

Lithium-ion batteries with aluminum anodes had appeared to resolve critical dendrite issues of lithium metal cells in the 1970s. However, the poor cycling attributed to aluminum anodes would lead to their obsolescence. In this work, we demonstrate how strategic thermal control circumvents the problematic α/β phase transformations. The electrochemical formation of Li3Al2 and Li2-xAl, which necessitates temperatures slightly above ambient, are the key enablers for high capacity and stable cycling. While delivering a competitive capacity level (ca. 1 Ah kg-1-Al), those higher-order phases exhibit significantly improved cycling behaviors, from a few cycles to one hundred cycles with ca. 67% capacity retention. Since modern battery charging is likely to occur above ambient due to ohmic heating, the thermal conditions explored here are likely to be realized in a variety of applications. Importantly, this elevated temperature is not necessary for aluminum anode delithiation, thus creating additional synergies with many practical scenarios.