Lithium-ion spontaneous exchange and synergistic transport in ceramic-liquid hybrid electrolytes for highly efficient...

Ceramic electrolytes are important in ceramic-liquid hybrid electrolytes (CLHEs), which can effectively solve the interfacial issues between the electrolyte and electrodes in solid-state batteries and provide a highly efficient Li-ion transfer for solid-liquid Li metal batteries. Understanding the ionic transport mechanisms in CLHEs and the corresponding role of ceramic electrolytes is crucial for a rational design strategy. Herein, the Li-ion transfer in the ceramic electrolytes of CLHEs was confirmed by tracking the ⁶Li and ⁷Li substitution behavior through solid-state nuclear magnetic resonance spectroscopy. The ceramic and liquid electrolytes simultaneously participate in Li-ion transport to achieve highly efficient Li-ion transfer in CLHEs. A spontaneous Li-ion exchange was also observed between ceramic and liquid electrolytes, which serves as a bridge that connects the ceramic and liquid electrolytes, thereby greatly strengthening the continuity of Li-ion pathways in CLHEs and improving the kinetics of Li-ion transfer. The importance of an abundant solid-liquid interface for CLHEs was further verified by the enhanced electrochemical performance in LiFePO₄/Li and LiNi_0.8Co_0.1Mn_0.1O₂/Li batteries from the generated interface. This work provides a clear understanding of the Li-ion transport pathway in CLHEs that serves as a basis to build a universal Li-ion transport model of CLHEs.