Abstract

Although research on the ceramic-polymer interface has been conducted in the field of composite solid electrolytes (CSEs), its principles have not been clearly identified. In this work, the Li ion conduction mechanism at a level where the ionic conductivity of the matrix is similar to that of the filler is studied. In addition, the oxygen vacancies (O-v) on the filler surface are filled through the ultraviolet ozone (UVO) process to confirm the difference in ion conduction because of the difference in interphase. When the O-v concentration is reduced, the ionic conductivity of the electrolyte increases compared to the existing electrolyte. Differences in resistance by electrolyte are identified through DRT analysis using a stainless steel (SS) symmetric cell. The surface-controlled electrolyte has a uniform ion flow, resulting in the formation of a stable solid electrolyte interphase (SEI) layer. Therefore, the electrolyte having a lower O-v on the filler surface shows better electrochemical performance, maintaining 92.47% of capacity at the 300th cycle.