Advanced Cathode Designs for High-Energy Lithium/Sodium-Selenium Battery

Selenium, with its superior conductivity, serves as a promising cathode material in lithium-selenium (Li-Se) and sodium-selenium (Na-Se) batteries, exhibiting faster electron transfer processes and volumetric capacity. Nonetheless, challenges such as volume expansion, the shuttle effect, slow redox reaction kinetics, and the low conductivity of discharged products still hinder their commercial application. Extensive research has been conducted on the design and optimization of cathode materials to overcome these issues. This review summarizes the latest advancements in Se cathode design within Li/Na-Se systems, based on the electrochemical mechanisms of batteries and the origins of related challenges. The comprehensive design principle of advanced and stable selenium cathodes is put forward, the key role of carbon structure design is analyzed, and the strategies to improve the affinity of selenide and redox kinetics are discussed. Additionally, it introduces representative polymer-based cathodes and metal-organic framework (MOF)-based cathodes. Some potential modification strategies for active materials are also highlighted, including selenium sulfide composite cathodes and lithium selenide cathodes, which can significantly enhance the electrochemical mechanisms of Se-based batteries. Finally, based on existing research, the related insights and directions for the future development of advanced Se cathodes are proposed.