UV-cured polymer electrolyte for LiNi0.85Co0.05Al0.1O2//Li solid state battery working at ambient temperature

A novel solid state polymer electrolyte with high ionic conductivity was fabricated by “solvent-free” photo-polymerization method and applied in solid state lithium battery with high-voltage cathode. The polymer structure was confirmed by FT-IR, and polymer electrolyte exhibits high ionic conductivity of 2.35×10−-4 S cm−1 at ambient temperature, wide electrochemical window of 0–4.63 V (vs. Li+/Li), excellent compatibility with lithium metal electrode for over 2000 h without short-circuit occurrence. Besides, LiMn0.8Fe0.2PO4 //Li batteries were assembled to evaluate battery performance, delivering maximum discharge capacity of 168.7 mAh g−1 at 0.1 C and 154.7 mAh g−1 at 0.5 C with capacity retention of 89.72% after 450th cycle at 60 °C. Also, the battery operated well at ambient temperature with capacity of 124.6 mAh g−1 and the capacity retention was 92.1% after 200 cycles. Importantly, the new polymer electrolyte is qualified to be applied in high-voltage cathode of LiNi0.85Co0.05Al0.1O2, delivering 108.8 mAh g-1 after 100th cycle at 0.5 C at 40 °C. The integrated cathode with electrolyte reducing interfacial resistance contributes excellent battery performance. The results demonstrate that this solid polymer electrolyte (SPE) is a promising candidate electrolyte for high energy density solid-state lithium metal battery.