Garnet-Poly(ε-caprolactone-<i>co</i>-trimethylene carbonate) Polymer-in-Ceramic Composite Electrolyte for All-Solid-State Lithium-Ion Batteries

A composite electrolyte based on a garnet (LLZO) and polyester-based co-polymer (80:20 ε-caprolactone (CL)-trimethylene carbonate, PCL-PTMC with LiTFSI salt) is prepared. Integrating the merits of both ceramic electrolytes expected to address poor ionic conductivity high interfacial resistance in solid-state lithium-ion batteries. The 80 wt % LLZO 20 polymer (PCL-PTMC lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) at 72:28 %) exhibited Li-ion 1.31 × 10–4 S/cm transference number (tLi+) 0.84 60 °C, notably higher than those pristine electrolyte. prepared also an electrochemical stability up 5.4 V vs Li+/Li. interface between LiFePO4 (LFP) cathode was improved by direct incorporation as binder coating. Li/composite electrolyte/LFP cell provided discharge capacity ca. 140 mAh/g suitable cycling 55 °C after 40 cycles. This study clearly suggests that this type amorphous polymers can be applied polymer-in-ceramic for realization advanced all-solid-state