In-situ construction of cellulose acetate propionate-based hybrid gel polymer electrolyte for high-performance lithium metal batteries

Abstract

Quasi-solid-state gel polymer electrolytes (GPEs) have a great deal of promise for usage in future energy systems due to their high safety. However, ex-situ prepared GPEs still suffer from interfacial incompatibility. Herein, to create stable electrolyte-electrode interfaces and ensure adequate contact, a novel GPE was prepared by in-situ polymerization using pentaerythritol tetraacrylate (PETEA) and cellulose acetate propionate (CAP) as raw materials. PETEA and CAP with a certain mass ratio were added into liquid electrolyte, and the in-situ polymerization of PETEA and CAP was initiated by azobisisobutyronitrile (AIBN). The multi-side chain structure of PETEA and the hydrogen bonding interaction between PETEA and CAP contributed to a robust cross-linked framework, while CAP improved Li+ transport through its polar oxygen-containing groups. The obtained GPE 1:1 exhibited high ionic conductivity (1.03 ×10−3 S/cm at 25 ℃), superior Li+ transference number (0.73), and good stability to Li metal. Meanwhile, a stable SEI film with rich LiF was established, ensuring a long-term cycling lifespan. After 500 cycles at 1 C, the assembled LiFePO4/GPE 1:1/Li cell revealed a high capacity retention of 90.6%. These results provide a guideline for the future design of novel cellulose-based GPEs for high performance lithium metal batteries.