Preparation and Electrochemical Properties of Bicontinuous Solid Electrolytes Derived from Porous Li6.4La3Zr1.4Ta0.6O12 Incorporated with Succinonitrile

The development of solid electrolytes is a key step to break through the technical bottleneck of lithium batteries and obtain lithium batteries with high safety and high energy density. Combining the advantages of both inorganic and organic solid electrolytes, the form of inorganic fillers for composite solid electrolytes is extended from nanoparticles, nanofibers to a 3D matrix. In this study, a porous Li6.4La3Zr1.4Ta0.6O12 (LLZTO) ceramic framework was fabricated by adding a pore-forming agent, which was then infiltrated by succinonitrile (SN)-LiTFSI to take full advantage of the inorganic and organic parts of the composite electrolyte. The interconnected porous structure allows continuous ion transport pathways in both parts. The effect of the porosity, namely the amount proportion of inorganic and organic materials, on the electrochemical performance of composite electrolytes was investigated by regulating the amount of pore-forming agent. The presented composite solid electrolyte achieves a very high ionic conductivity of 1.08 × 10−3 S cm−1 at 30 °C, while it is stable up to 5.1 V at room temperature. The repeated lithium stripping/plating is stable over 250 h without short circuit.