Molecular organic solid-state electrolytes (MOSSEs): a review of an overlooked class of solid electrolytes

at ambient temperatures. MOSSEs also possess a low Young's modulus, improving electrode-electrolyte contact and lowering interfacial resistance, while facilitating processing and cell fabrication. We analyze the synthesis methods, structural characteristics, ion transport mechanisms, electrochemical stability windows, and battery performance of various MOSSE systems. Challenges such as moderate thermal stability and limited scalability are addressed, alongside strategies to improve interfacial compatibility and expansion of their electrochemical stability window. By overcoming key limitations of conventional solid electrolytes, such as brittleness, poor electrode-electrolyte contact, and high-temperature processing, MOSSEs offer a promising path toward safer, high-performance solid-state batteries for lithium and beyond-lithium systems.