The failure of Li metal anodes can be attributed to their unstable electrode/electrolyte interface, especially the continuous formation of solid electrolyte interphase (SEI) and dendrite growth. To address this challenge, scholars proposed the construction of artificial SEI (ASEI) as a promising strategy. The ASEI mainly homogenizes the distribution of Li⁺, mitigates dendrite growth, facilitates Li⁺ diffusion, and protects the Li metal anode from electrolyte erosion. This review comprehensively summarizes the recent progress in the construction of ASEI layers in terms of their chemical composition. Fundamental understanding of the mechanisms, design principles, and functions of the main components are analyzed. We also propose future research directions to facilitate the in-depth study of ASEI and its practical applications in Li metal batteries. This review offers perspectives that will greatly contribute to the design of practical Li metal electrodes.

High-performance lithium-ion batteries (LIB) are important in powering emerging technologies. Cathodes are regarded as the bottleneck of increasing battery energy density, among which layered oxides are the most promising candidates for LIB. However, a limitation with layered oxides cathodes is the transition metal and Li site mixing, which significantly impacts battery capacity and cycling stability. Despite recent research on Li/Ni mixing, there is a lack of comprehensive understanding of the origin of cation mixing between the transition metal and Li; therefore, practical means to address it. Here, a critical review of cation mixing in layered cathodes has been provided, emphasising the understanding of cation mixing mechanisms and their impact on cathode material design. We list and compare advanced characterisation techniques to detect cation mixing in the material structure; examine methods to regulate the degree of cation mixing in layered oxides to boost battery capacity and cycling performance, and critically assess how these can be applied practically. An appraisal of future research directions, including superexchange interaction to stabilise structures and boost capacity retention has also been concluded. Findings will be of immediate benefit in the design of layered cathodes for high-performance rechargeable LIB and, therefore, of interest to researchers and manufacturers.

The emergence of anionic redox reactions in layered transition metal oxide cathodes provides practical opportunity to boost the energy density of rechargeable batteries. However, the activation of anionic redox reaction in layered oxides has significant voltage hysteresis and decay that reduce battery performance and limit commercialization. Here, we critically review the up-to-date development of anionic redox reaction in layered oxide cathodes, summarize the proposed reaction mechanism, and unveil their connection to voltage hysteresis and decay based on the state-of-the-art progress. In addition, advances associated with various modification approaches to mitigate the voltage hysteresis/decay in layered transition metal oxide cathodes are also included. Finally, we conclude with an appraisal of further research directions including rational design of high-performance layered oxide cathodes with reversible anionic redox reactions and suppressed voltage hysteresis/decay. Findings will be of immediate benefit to the development of layered oxide cathodes for high performance rechargeable batteries.

The key role played by carbon dioxide in global temperature cycles has stimulated constant research attention on carbon capture and storage. Among the various options, lithium–carbon dioxide batteries are intriguing, not only for the transformation of waste carbon dioxide to value-added products, but also for the storage of electricity from renewable power resources and balancing the carbon cycle. The development of this system is still in its early stages and faces tremendous hurdles caused by the introduction of carbon dioxide. In this review, detailed discussion on the critical problems faced by the electrode, the interface, and the electrolyte is provided, along with the rational strategies required to address these problematic issues for efficient carbon dioxide fixation and conversion. We hope that this review will provide a resource for a comprehensive understanding of lithium–carbon dioxide batteries and will serve as guidance for exploring reversible and rechargeable alkali metal-based carbon dioxide battery systems in the future.