Distinct Dynamics of Lithium Intercalation and Plating on Graphite Anode for Li‐Ion Batteries in eVTOL Applications

Abstract In the absence of viable high‐energy‐density battery alternatives, lithium‐ion (Li‐ion) batteries remain essential for enabling electric vertical take‐off and landing (eVTOL) platforms in advanced air mobility. Unlike Li‐ion batteries used in electric vehicles and portable electronics, eVTOL battery systems operate under distinct high‐power demands, which necessitate an independent assessment of material degradation mechanisms. This study presents a case analysis of graphite anode evolution under high‐power cycling conditions. The findings reveal lithium entrapment within graphite particles, potentially resulting from incomplete Li‐ion de‐intercalation during a high‐rate discharge event that is characteristic of eVTOL take‐off and landing. This phenomenon leads to a progressive reduction in graphite‐specific capacity and, over time, promotes lithium metal plating on the anode. Notably, the Li‐metal plating observed in this study differs from that associated with fast‐charging conditions, as it is primarily governed by concentration polarization‐induced overpotential in the latter case. These findings highlight the inherent challenges of utilizing graphite in high‐power Li‐ion battery applications and elucidate the unique degradation mechanisms that arise due to the sluggish reaction kinetics of Li‐ion intercalation and de‐intercalation within graphite.