Recent advances in vacancy engineering for reliable lithium-sulfur batteries

The high-energy-density and low-cost features endow lithium-sulfur batteries with broad application prospects. However, many drawbacks, especially the detrimental shuttle effect, have hindered the further development of LSBs. In response, a lot of new structures have been applied to suppress the shuttle effect and promote the development of LSBs. Recently, vacancy engineering has gained the attention of researchers due to its unique electronic structure. This review aims to analyze the application of vacancy engineering in LSBs. Firstly, the electrochemistry of LSBs has been systematically discussed and the existing challenges as well as improvement tactics of LSBs have also been presented. Subsequently, the preparation methods and characterization technologies of various vacancies are summarized, including oxygen vacancies, sulfur vacancies, selenium vacancies, other anion vacancies, cation vacancies, etc. The latest applications of vacancy engineering in LSBs are also summarized in this review. Finally, some prospects and insights for further investigation and practical application of vacancy engineering in LSBs are put forward.