Ionic Percolation Networks in Composite Electrodes for All-Solid-State Batteries

Abstract

As the demand for high performance lithium-ion batteries grows, materials research isneeded to provide a safer alternative to the use of flammable liquid electrolytes. All-solid-state composite electrolytes consisting of a polymer host and ceramic filler can balance both the need for high ion-conductivity and mechanical flexibility within operating battery systems. The high interfacial resistances between such electrolytes and electrodes, as well as within porous electrodes, however, is a prohibitive performance attribute characteristic of this class of materials. One strategy to mitigate the inhibitory diffusion kinetics associated with the interface is to introduce an ionic percolation network into the electrodes. This work makes use of a composite electrolyte made of an ionically conductive garnet filler Li6.4La3Zr1.4Ta0.6O12 (LLZTO) and a poly(ethylene oxide) (PEO)-lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) polymer-salt complex matrix as a model composite electrolyte system to study the effects of ionic percolation in porous powdery electrodes. The effects of using an ionically conductive polymer consisting of PEO and LiTFSI as a pore filler in both cathode and anode electrodes on the performance of an all-solid-state lithium-ion battery are studied.