The pursuit of solid-state electrolytes for lithium batteries: from comprehensive insight to emerging horizons

Conventional lithium rechargeable batteries contain solid electrodes and liquid electrolytes, which can have potential security risks concerning volatilization, flammability and explosion. Demand for safe, high-energy lithium-ion batteries is increasing. Solid-state electrolytes could eliminate most of the safety concerns encountered with liquid electrolytes. In this review, we discuss existing solid electrolytes including inorganic solid electrolytes, solid polymer electrolytes, and composite solid electrolytes. We systematically summarize and visually display the current limitations of solid electrolytes and efforts to overcome them with the objective of large-scale development. The development of flexible, lithium-sulfur and lithium-air batteries containing solid electrolytes is described. The Materials Genome Initiative, which was designed to allow efficient selection of solid electrolytes, is also introduced.