Lithium-Ion Transport and Exchange between Phases in a Concentrated Liquid Electrolyte Containing Lithium-Ion-Conducting Inorganic Particles

Understanding Li⁺ transport in organic-inorganic hybrid electrolytes, where Li⁺ has to lose its organic solvation shell to enter and transport through the inorganic phase, is crucial to the design of high-performance batteries. As a model system, we investigate a range of Li⁺-conducting particles suspended in a concentrated electrolyte. We show that large Li_1.3Al_0.3Ti_1.7P₃O₁₂ and Li₆PS₅Cl particles can enhance the overall conductivity of the electrolyte. When studying impedance using a cell with a large cell constant, the Nyquist plot shows two semicircles: a high-frequency semicircle related to ion transport in the bulk of both phases and a medium-frequency semicircle attributed to Li⁺ transporting through the particle/liquid interfaces. Contrary to the high-frequency resistance, the medium-frequency resistance increases with particle content and shows a higher activation energy. Furthermore, we show that small particles, requiring Li⁺ to overcome particle/liquid interfaces more frequently, are less effective in facilitating Li⁺ transport. Overall, this study provides a straightforward approach to study the Li⁺ transport behavior in hybrid electrolytes.