Formation of Excellent Cathode/Electrolyte Interface with UV-Cured Polymer Electrolyte through In Situ Strategy

UV-cured polymer electrolyte is synthesized via photo-polymerization of poly (ethylene glycol) methyl ether methacrylate and poly (ethylene glycol) diacrylate. The obtained polymer electrolyte exhibits a high ionic conductivity of 2.95 × 10 −5 S cm −1 at 30 °C, a wide electrochemical stable window of up to 4.69 V (vs Li/Li + ) and excellent compatibility against lithium metal electrode over 800 h. Besides, an integrated cathode/electrolyte interface is constructed through pouring the polymer electrolyte precursor onto the cathode layer. This kind of the integrated cell exhibits faster Li-ion diffusion in cathodic electrochemical reactions than conventional cells. Moreover, LiMn 0.8 Fe 0.2 PO 4 ∣∣Li cells with integrated cathode/electrolyte interface deliver a reversible capacity of 164.7 mAh g −1 at 0.1C and retains a capacity of 134.4 mAh g −1 after 240 cycles at 0.2C. Furthermore, the integrated cells show satisfactory performance under disastrous conditions, presenting their high safety. The UV cross-linked polymer electrolyte is a promising polymer electrolyte candidate for high energy density all-solid-state lithium metal batteries.