A Review of Solid-State Lithium–Sulfur Battery: Ion Transport and Polysulfide Chemistry

The lithium–sulfur (Li–S) battery has long been a research hotspot due to its high theoretical specific capacity, low cost, and nontoxicity. However, there are still some challenges impeding the Li–S battery from practical application, such as the shuttle effect of lithium-polysulfides (LiPSs), the growth of lithium dendritic, and the potential leakage risk of liquid electrolytes. Substitution of liquid electrolytes with solid-state electrolytes (SSEs) is an effective strategy to relieve or even solve these problems. This review focuses on the most crucial issues of the solid-state Li–S battery (SSLSB) and exhibits the recent progress in these fields. SSEs applicable in the Li–S battery including inorganic glassy ceramics and ceramics, organic polymers, and inorganic–organic hybrid electrolytes are reviewed. Then, the establishment of Li-ion pathways inside the cathode is discussed in detail. We also probe into the unique polysulfide chemistry of the Li–S battery and expound our opinions. Finally, conclusions and perspectives are outlined for the further development of SSLSBs.