In situ construction of 3D crossing-linked gel polymer electrolyte toward high performance and safety lithium metal batteries
Huilan Li, Tingting Feng, Jian Gao, Mengqiang Wu
Abstract
Our study focuses on developing high-performance gel polymer electrolytes (GPEs) tailored for lithium metal batteries (LMBs), harnessing the combined benefits of high conductivity of liquid electrolytes and the enhanced safety of solid electrolytes . To this end, we engineered an in situ polymerized GPE (PMIA- TP) that integrates trifluoroethyl methacrylate (TFMA) and pentaerythritol triacrylate (PETA) monomers within an electrospun poly ( m -phthaloyl- m -phenylenediamine) (PMIA) supporting membrane. In addition to high ionic conductivity , high lithium ion transference number, enhanced tensile strength and good thermal stability , the resulting PMIA-TP GPE exhibits satisfactory electrochemical stability against lithium electrodes, enabling long-term and stable lithium plating/stripping in symmetric Li//Li cells, and good rate capability and prolonged cycle life for LiFePO 4 //Li cells. Further X-ray photoelectron spectroscopy analysis and density functional theory calculations revealed that the electrochemical stability of the PMIA-TP GPE towards lithium metal electrode is due to the formation of a fluorine-rich solid electrolyte interphase (SEI) layer facilitated by reactions involving the –CF 3 groups in TFMA, which is beneficial for the effective Li + transport and lithium dendrite suppression. In summary, our study offers a promising approach to fabricating GPEs that offer high safety and high performance for LMBs.