Inorganic-organic gel electrolytes with 3D cross-linking star-shaped structured networks for lithium ion batteries

Abstract

Abstract Inorganic–organic electrolytes with 3D cross-linking star-shaped structured networks (3D-GPEs), consisting of multifunctional epoxy POSS and rich EO unites, are proposed for lithium ion batteries. Here, multifunctional epoxy POSS, epoxy and amino monomers containing rich EO units are chosen to build tough and compact 3D network membranes as host polymer to guarantee fast ion transport through epoxy ring-open polymerization with no initiator or no small molecule by-products generating. The electrochemical properties of 3D-GPEs and the performances of Li/LiFePO4 cells assembled with 3D-GPEs were investigated. As a result, the ionic conductivity of 3D-GPEs containing POSS is up to 2.35 × 10−3 S cm−1 at room temperature, which is almost two times than that of the GPEs without POSS. The electrochemical windows of the 3D-GPEs containing POSS are wide up to 5.25 V, indicating excellent electrochemical stability. The Li/3D-GPEs/LiFePO4 batteries exhibit good cycling performance and high rate capability. Moreover, Li/LiFePO4 cells assembled with 3D-GPEs containing POSS deliver higher discharge capacity. The discharge capability of LiFePO4/ 3D-GPE/Li is 148 mAh g−1 with excellent capacity retention after 80th cycle at 0.1C at room temperature.