Review—Solid Electrolytes for Safe and High Energy Density Lithium-Sulfur Batteries: Promises and Challenges

All-solid-state lithium-sulfur batteries (ASSLSBs) offer a means to enhance the energy density and safety of the state-of-art lithium-ion batteries (LIBs), due to their high gravimetric energy density, low cost and environmental benignancy. In this work, the status of the research advances and perspectives on several types of solid electrolytes (SEs) developed for ASSLSBs are reviewed. The promises and challenges of utilizing SEs are discussed taking into account both theoretical calculation and experimental results, in hope of shedding some lights on future design of high energy density, cost competitive, and safe Li-S batteries.