High-Conductivity Solid-State Electrolytes Through Low-Temperature Hot-Pressing of LCBA/LATP Composites

Solid-state electrolytes (SSEs) are essential for achieving long-term stability and fast-charging performance in secondary batteries. Although Li1.3Al0.3Ti1.7(PO4)3 (LATP) offers high ionic conductivity, its practical application is restricted by high-temperature sintering requirements and interfacial reduction at the lithium anode. In contrast, Li-based oxide electrolytes can be sintered below 600 °C, offering improved compatibility with conventional electrodes such as graphite and silicon. In this study, a Li2O–LiCl–B2O3–Al2O3 (LCBA)/LATP composite SSE was fabricated via hot-press co-sintering at 600 °C. Composites with LCBA:LATP weight ratios of 8:2, 7:3, 6:4, 5:5, 3:7, and 2:8 were prepared to identify the optimal composition. The 3:7 composite achieved a sintered density of 2.40 g/cm3 and an ionic conductivity of 2.5 × 10−4 S/cm. Phase evolution and sintering behavior were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). Compared to single-phase LCBA or LATP, the composite electrolyte exhibited improved interfacial stability and lower interfacial resistance against lithium metal.