A review on recent advancements in solid state lithium-sulfur batteries: fundamentals, challenges, and perspectives

Lithium-sulfur (Li-S) batteries (LSBs) have recently attracted extensive attention in the energy storage sector due to their very high theoretical energy density, and low cost of active materials compared to the state-of-the-art Li-ion batteries. Despite recent progress in both the electrode and electrolyte materials and fundamental understanding the practical use of conventional LSBs is still hindered by their safety concerns and poor cycling performance. Solid-state LSBs (SSLSBs) have great potential to surmount these challenges. This review describes the basic requirements of solid-state electrolytes (SSEs) and the fundamental understanding of solid electrolytes by addressing the key issues in the areas of ion transport. We emphasize recent advances in various SSEs used in SSLSBs. We also address the challenges and plausible solutions, involving improved designs and compositions of SSEs, electrode materials, and electrode-electrolyte interfaces. Even though several technological and fundamental issues still need to be solved to develop commercially viable technologies, SSLSBs offer a great opportunity to deal with the present limitations.