Research on the Mechanism of Space Charge Layer in Gel Electrolyte: Synergistic Effects of PFPE Networks and Li₂O

Abstract

The increasing demand for energy in portable electronics and electric vehicles has highlighted the necessity for lithium-ion batteries that offer high energy density, safety, and long cycle life. To address this challenge, this study introduces a novel gel polymer electrolyte (GPE) based on a poly(vinylidene fluoride-co-hexafluoropropylene)-perfluoropolyether methacrylate (PH-PFPE) 3D network structure, integrated with lithium oxide (Li₂O) fillers that form a space charge layer (SCL). Lithium metal batteries (LMBs) utilizing this new gel electrolyte demonstrate exceptional rate performance across a broad current density range (0.2 to 4 C) and retain 95.64% of their capacity after 1500 cycles at 3 C. This paper provides a comprehensive analysis of the microstructure and interfacial properties of both the electrode materials and gel electrolytes. Furthermore, molecular dynamics simulations reveal the molecular-level synergistic effect between the polymer and fillers, which significantly enhances lithium-ion transport.