Composite Polymer Electrolyte with Vertically Aligned Garnet Scaffolds for Quasi Solid-State Lithium Batteries

Structure design is of great importance for composite solid electrolytes to meetthe high requirements for lithium batteries today. Herein, a novel composite polymerelectrolyte with vertically aligned fast ion pathways has been constructedthrough the in-situ UV-induced polymerization of poly (butyl acrylate) (PBA)based gel polymer electrolyte inside the honeycomb-structure Li6.5La3Zr1.5Ta0.5O12(LLZTO) scaffolds by freeze casting. The addition of LLZTO enhances the anionadsorption through the Lewis-acid sites from La ions and reduces the Li+complexation by participating in the interaction of C=O...Li+. Therefore, the interfaceof PBA and LLZTO scaffold serves as a continuous Li+ transport pathwayand the resulting composite solid electrolyte exhibits a high ionic conductivity(5.098 × 10−4 S cm−1), near single-ion conducting characteristic (a transferencenumber of 0.8) and high electrochemical stability window (5.15 V). Based on theabove superior performance, the composite electrolyte promotes uniform distributionof lithium ion concentration and electrolyte potential. Thus, quasi-solidstateLiFePO4/Li cells exhibit excellent cycling performance (capacity retentionof 91.7% after 300 cycles at 0.5 C).