Breaking Solvation Dominance of Phosphate via Dipole–Dipole Chemistry in Gel Polymer Electrolyte

A prevalent method to bolster the safety of lithium-ion batteries (LIBs) is through the deployment of phosphate-based electrolytes. Nonetheless, an intrinsic challenge arises from the incompatibility between phosphate components and graphite anodes, a phenomenon known as coinsertion. To tackle this obstacle, we introduce a comprehensive strategy that employs in situ thermal polymerization, leveraging a flame-retardant solvent and a polymer matrix. This approach fosters strong dipole–dipole interactions between phosphate molecules and the polymer matrix, effectively alleviating the adverse impacts on graphite anodes. This significant enhancement is validated through in situ X-ray diffraction, X-ray photoelectron spectroscopy depth profile analysis, and transmission electron microscopy imaging. Our methodology facilitated stable lithium-ion operations within electrolytes comprising 20% phosphate components in assembled NCM811|P-GPE|Gr pouch cells, achieving a low-capacity decay rate of 0.0023% per cycle with good flame-retardant characteristics. We believe this strategy heralds new commercial prospects for incorporating phosphate-based solvents in the creation of exceptionally safe LIBs.