Ambient-stable cathode-level solid electrolyte via wetting-controlled surface molecular modification

초록

Sulfide solid electrolytes offer high ionic conductivity and favorable processability for all-solid-state batteries, yet their air instability remains a critical challenge, particularly for cathode-grade fine particles required in composite cathodes. In this work, we introduce an ultra-low surface energy molecular passivation (SEMP) strategy based on perfluorodecanethiol to stabilize argyrodite solid electrolytes under practically relevant ambient conditions (31% RH, 22 degrees C). Particle-size-dependent spectroscopic analyses reveal that cathode-grade electrolytes experience accelerated surface degradation driven by increased surface-to-volume ratios and diffusion kinetics. These degradation pathways are effectively suppressed by SEMP through chemically robust thiol anchoring and an ultralow-surface-energy perfluorinated tail. Asa result, SEMP-treated cathode-grade electrolytes exhibit a slow ionic conductivity degradation rate and retain stable conductivity after 100 h of air exposure. Cell-level evaluations further demonstrate that, unlike pristine cathode-grade electrolytes that fail within 20 cycles after air exposure, SEMP-treated catholytes maintain stable interfacial behavior and prolonged cycling performance. (c) 2026 Science Press and Dalian Institute of Chemical Physics, Chinese Academy of Sciences. Published by Elsevier B.V. and Science Press. All rights are reserved, including those for text and data mining, AI training, and similar technologies.

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