The article by Gaurav Assat and Jean-Marie Tarascon discusses the fundamental understanding and practical challenges of anionic redox activity in lithium-ion batteries. Anionic redox, which involves the redox of ligands in Li-rich Mn-based layered oxides, has emerged as a promising approach to enhance the energy storage capacity of these batteries. The authors review the historical development of anionic redox, the underlying science, and the practical limitations of anionic-redox-based materials. They highlight the need for understanding the relative positions of cationic and anionic levels to design novel materials with improved performance. The article also explores the challenges in practical applications, such as voltage hysteresis, sluggish kinetics, and oxygen release, and discusses potential solutions. Despite these challenges, the authors remain optimistic about the future of anionic redox in Li-ion batteries, emphasizing the importance of theoretical and experimental advancements to overcome current limitations.The article by Gaurav Assat and Jean-Marie Tarascon discusses the fundamental understanding and practical challenges of anionic redox activity in lithium-ion batteries. Anionic redox, which involves the redox of ligands in Li-rich Mn-based layered oxides, has emerged as a promising approach to enhance the energy storage capacity of these batteries. The authors review the historical development of anionic redox, the underlying science, and the practical limitations of anionic-redox-based materials. They highlight the need for understanding the relative positions of cationic and anionic levels to design novel materials with improved performance. The article also explores the challenges in practical applications, such as voltage hysteresis, sluggish kinetics, and oxygen release, and discusses potential solutions. Despite these challenges, the authors remain optimistic about the future of anionic redox in Li-ion batteries, emphasizing the importance of theoretical and experimental advancements to overcome current limitations.