Critical Parts for Fast-Charging Lithium Batteries: A Review of Electrolytes

Fast-charging lithium batteries (LBs) are regarded as a key technical aspect for electric vehicles (EVs) and advanced energy storage systems. However, their practical application is still severely hindered due to the slow lithium-ion transfer, unstable interfaces, severe polarization, and safety issues during high-rate operation. Among the various strategies developed to address these challenges, electrolyte engineering has emerged as one of the most effective and economically viable approaches. This review first provides a detailed account of the critical processes related to electrolytes that determine the fast-charging performance of LBs, as well as the current challenges faced by electrolyte design. Then, recent advances in electrolyte design for fast-charging LBs are summarized from the perspectives of new materials discovery and emerging formulation strategies, which are highlighted with encouraging examples to demonstrate how electrolyte chemistry can be used to improve the fast-charging performance via reconciling the trade-offs among fast ion transport, interfacial stability, wide-temperature adaptability, high-voltage compatibility, and safety concerns. Finally, the remaining challenges and future opportunities are outlined and discussed. This review aims to provide a comprehensive understanding of fast-charging processes related to electrolytes and to provide useful guidance for the rational design of next-generation electrolytes for high energy density and safe LBs.