Passivation and corrosion of Al current collectors in lithium-ion batteries

State-of-the-art lithium-ion batteries inevitably suffer from electrode corrosion over long-term operation, notably corrosion of Al current collectors. Here, we evaluate Al corrosion and its impacts on battery performance. Passivation, passivity breakdown, and corrosion of Al deteriorate the solid/solid interface and electrode integrity. Localized diffusion of F−/Al3+ introduces irreversible current detrimental to Coulombic efficiency (1.14% loss). Over battery life, this behavior leads to extensive capacity damage (>20%). During cycling, a passivation layer (>20 nm) forms near the median voltage. As charging voltage rises, newly formed Al–F–O particles squeeze and deform the passivation layer, inducing stress corrosion cracks. The passivation layer peels off and is re-generated as voltage continues rising, repeatedly consuming the Al matrix. Passivity breakdown with localized corrosion is derived from ethylene carbonate adsorption and correlates strongly with charge voltages, especially at 4.4 V and 4.8 V. These results benchmark electrode corrosion in advanced energy storage materials and are crucial for electrode engineering and performance modulation via interfacial design.