(435f) Gel Polymer Electrolyte with Ionic Liquid Modified Carbon Nanotubes for Fast Charging Lithium Metal Batteries

Fast charging is a critical requirement for next-generation energy storage devices, but the high ions flux can lead to uncontrolled growth of lithium dendrites and unstable solid electrolyte interface (SEI) films. Additionally, the organic liquid electrolytes used in commercial are flammable and electrochemically unstable, which increases the potential risk of fire or explosion after liquid electrolytes leakage during fast charging. Using solid-state electrolytes instead of liquid electrolytes is an effective solution to the above problems. In this study, we introduce a gel polymer electrolyte (GPE) based on polyvinylene carbonate (PVCA), poly (ethylene oxide) (PEO), poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), and ionic liquid modified carbon nanotubes (IL-CNTs) by solution casting method. On the one hand, the synergistic combination of PEO and PVCA modulates the interaction strength with lithium ions and provides the necessary flexibility and rigidity for optimal performance. On the other hand, the IL-CNTs nanofillers reduce polymer crystallinity and enhance ionic conductivity, resulting in an ionic conductivity of 7.1 × 10^-4 S cm^−1 at 30°C. The GPE also exhibits an electrochemical window of 4.74 V due to the mechanical strength enhancement function of IL-CNTs. Furthermore, the LiFePO₄ cell can cycle stably for 1000 cycles at a high rate of 4C. This study marks a step towards the development of efficient and safe fast charging lithium metal batteries.