The Polymer Society of Korea

송영진 (포항공과대학교)

박수진 (포항공과대학교)

The demand for high-energy-density and safe energy storage has accelerated the development of all-solid-state batteries (ASSBs). To address interfacial instability in ASSBs with sulfide solid electrolytes (SSEs), we propose a strategy using submicron-thick functional polymer films deposited via initiated chemical vapor deposition. Eight polymers were evaluated, and poly(acrylic acid) (pAA) and poly((perfluorohexyl)ethyl acrylate) (pC6FA) significantly improved coulombic efficiency (CE) and cycling stability. These coatings protect anodes from direct SSE contact and enable tailored solid-electrolyte interphase (SEI) formation. In@pAA and In@pC6FA achieved CE >98.8% with favorable SEIs—Li₂CO₃/COO⁻Li for pAA and LiF/LixPOyFz for pC6FA—confirmed by XPS and TOF-SIMS, while others led to Li₂S formation and poor CE. Our findings offer insight into previously underexplored polymer–SSE interactions and provide a platform for interfacial design in high-performance ASSBs.