Challenges and Strategy on Parasitic Reaction for High‐Performance Nonaqueous Lithium–Oxygen Batteries

The soaring demands for large‐scale energy storage devices have triggered great interest in nonaqueous lithium–oxygen batteries (LOBs), the most promising next‐generation rechargeable batteries due to their extremely high energy density, low cost, and environmental friendliness. However, serious parasitic reactions give rise to continuous consumption of cell components and accumulation of indissoluble side products, resulting in high overpotential, low rate capability, and especially limited cycle life, which hinder the commercial application of LOBs. This review focuses on comprehensively understanding the possible parasitic reactions involved at the cathode, anode, and electrolyte engendered by reactive oxygen species, impurity gasses, and singlet oxygen, while other factors that destabilize batteries such as Li dendrites, high potential, and incompatibility of cell components are also discussed. Furthermore, the corresponding strategies to inhibit or eliminate parasitic reactions and enhance the cycle stability are elaborated from the perspectives of composition regulation, microstructural design, and alternative components. It should be emphasized that the introduction of dual redox mediators and singlet quencher is crucial to achieve efficient LOBs with high capacity and prolonged cycle life. Finally, perspectives on suppressing parasitic reaction are proposed with the purpose of providing inspiration in designing stable LOBs for practical applications. This review summarizes the main culprits that are responsible for the primary parasitic reactions of nonaqueous Li–O2 batteries. Corresponding strategies to inhibit or eliminate parasitic reactions are elaborated with respect to cathodes, anodes, and electrolytes, respectively. Finally, perspectives toward suppressing parasitic reaction are proposed with the purpose of providing inspiration in designing stable Li–O2 batteries for practical applications.