Effects of porosity and ionic liquid impregnation on ionic conductivity of garnet-based flexible sheet electrolytes

Although the garnet-type ceramic ionic conductor, Li7La3Zr2O12 (LLZO), shows relatively high chemical stability against Li metal and has the potential to replace flammable liquid electrolytes for Li metal batteries, the large interfacial resistance between LLZO and electrodes challenges its practical application. A possible solution is to produce a quasi-solid-state LLZO-based flexible sheet electrolyte. Here we prepared an Al-doped LLZO-based flexible sheet electrolyte and studied its ionic conductivity as functions of porosity and ionic liquid (IL) impregnation. Possible Li+ ion conducting pathways through the quasi-solid-state composite sheet electrolyte were discussed and its electrochemical performance was also evaluated.