The effect of mixed salts in gel-coated polymer electrolyte for advanced lithium battery

Abstract A miscible blend solution of poly(ethylene glycol diacrylate) (PEGDA)/poly(vinylidene fluoride) (PVdF)/poly(methyl methacrylate) (PMMA) was crosslinked on polypropylene (PP) separator by UV-irradiation. PEGDA/PVdF/PMMA(E/V/M)-coated electrolytes showed much better liquid electrolyte uptaking and retention than PEGDA/PP composite electrolyte because viscous ternary blend solution was more compatible with electrolyte system. Gel-coated membranes (GCE) containing a mixed lithium salts of LiPF 6 /LiCF 3 SO 3 (10/1 (w/w)) showed slightly lower maximum conductivity than those containing only LiPF 6 , but their interfacial resistance much more stable than other salt compositions. In addition, it was found that γ-Al 2 O 3 filler improved interfacial stability. As a result, 8 cm × 13 cm MCMB/LiCoO 2 cells composed of E/V/M-coated composite matrix and LiPF 6 /LiCF 3 SO 3 (10/1 (w/w)) delivered 99.6% initial capacity after 100 cycles at C /2 rate.