Garnet-type solid-state electrolytes (SSE) have garnered considerable interest because of their high ionic conductivity and broad electrochemical window. However, poor interfacial contact with lithium metal remains a persistent challenge, leading to insufficient interfacial stability and low rate performances of the SSE. In this study, the surface of the garnet LLZTO (Li6.45Al0.05La3Zr1.6Ta0.4O12) SSE pellet is integrated with a nanoscale Li4Ti5O12 (LTO) through application of TiO2 using atomic layer deposition (ALD). The 2.5 nm TiO2 layer reacts with Li2CO3 on the surface and grain boundaries of LLZTO pellet to form the nanoscale Li4Ti5O12 (LTO) during the sintering process. The integrated nanoscale LTO enhances the wettability of LLZTO SSE with lithium metal and reduces the grain boundary resistance, providing a stable and zero-strain channel for lithium deposition and stripping. These features promote uniform lithium deposition and rapid lithium ion migration through LLZTO, thereby suppressing lithium dendrite formation and achieving high rate performance. These findings offer new insights into the surface modification strategies for garnet-type SSE aimed at improving their wettability, interfacial stability, and rate capability in lithium battery.
Chang et al. (2025) studied this question.