Synergistic interactions between the charge-transport and mechanical properties of the ionic-liquid-based solid polymer electrolytes for solid-state lithium batteries

The performance sensitivity of the solid-state lithium cells to the synergistic interactions of the charge-transport and mechanical properties of the electrolyte is well acknowledged in the literature, but the quantitative insights therein are very limited. Here, the charge-transport and mechanical properties of a polymerized ionic-liquid-based solid electrolyte are reported. The transference number and diffusion coefficient of lithium in the concentrated solid electrolyte are measured as a function of concentration and stack pressure. The elastoplastic behavior of the electrolyte is quantified under compression, within a home-made setup, to substantiate the impact of stack pressure on the stability of the Li/electrolyte interface in the symmetric lithium cells. The results spotlight the interaction between the concentration and thickness of the solid electrolyte and the stack pressure in determining the polarization and stability of the solid-state lithium batteries during extended cycling.