Advanced additive engineering for high-electrochemical-performance lithium-ion batteries

Advanced additives have become a key strategy for pushing the practical limits of lithium-ion batteries (LIBs) by tuning not only electrode materials but the entire cell structure. Instead of being passive bystanders, modern additives are intentionally designed to participate in electrochemical reactions, buffer mechanical stress, regulate ion and electron transport, and form robust interphases. This review offers a comprehensive overview of how additives are used in anodes, electrolytes, and cathodes to improve energy density, rate capability, cycle life, and overall safety. We explain how tailored additives can stabilize active materials that undergo significant volume changes, facilitate the formation of thin, stable, and conductive interphases, and enhance Li⁺ solvation and transport, thereby mitigating lithium plating and side reactions. Special attention is given to multifunctional additives that provide structural reinforcement, redox activity, and interface engineering, along with the interplay between bulk modifications and surface design strategies. Finally, we discuss ongoing challenges, including compatibility with high-voltage chemistries, scalability, and performance in practical cell formats, and we propose future directions for data-driven, rational additive development. By viewing additives as active, designable components of the entire battery system, this review aims to support the development of advanced LIBs with improved durability, safety, and performance under real-world conditions. • Modern additives play an active role in electrochemical reactions, surpassing traditional passive functions. • Multifunctional additives enhance structural integrity, exhibit redox activity, and stabilize interfaces. • Customized additives enhance energy density, improve rate capability, extend cycle life, and increase battery safety. • Data-driven design strategies facilitate the rational integration of both bulk and surface modifications for the effective development of high-voltage LIBs.