Mechanistic Considerations for Battery Charging Protocol Design

ABSTRACT The rapid growth of lithium‐ion batteries (LIBs) applications drives the need for fast‐charging solutions ensuring speed, safety, durability, and performance. Such charging protocol design needs to be guided by mechanistic understanding of degradation pathways, ionic transport limitations, and thermal constraints. However, in practice, many charging protocols used in commercial electronics and electric vehicles (EVs) have limited mechanistic transparency. In this review, we adopt a reverse perspective by extracting mechanistic insights from practical charging protocols to inform future design. To this end, standardized fast‐charging protocols and those implemented in real‐world applications such as smartphones and EVs are analyzed to examine how their voltage–current profiles evolve with state‐of‐charge (SOC) and to reflect distinct design rationales. These features are further examined in terms of SOC‐dependent physical and chemical transformations in electrode materials, kinetic limitations such as polarization and reaction heterogeneity influenced by charging protocol design, and distinct heat generation patterns governed by protocol characteristics. Advanced characterization techniques are then highlighted for providing real‐time insights into structural transitions, diffusion kinetics, and heat evolution during fast charging. Finally, future protocol design may be informed by multiscale material modelling, real‐time sensing for adaptive control, and data‐driven optimization to support the development of advanced fast‐charging systems.