Preparation of hybrid polymer based on polyurethane lithium salt and polyvinylidene fluoride as electrolyte for lithium-ion batteries

摘要

In this paper, hybrid microporous gel polymer electrolytes (HMGPEs) based onpolyvinylidene fluoride (PVdF)/polyurethane lithium salt (PLS) are fabricated by thermal phase separation technique. PIS is synthesized via condensation copolymerization of polyethylene glycol 800 (PEG800) and diphenyl-methane-diisocyanate(MDI), and then neutralized with LiOH. The effect of PLS on the morphologies of the hybrid membrane, electrochemical properties and cycle performance of the assembled polymer lithiumion rechargeable batteries are studied in detail. The morphologies of the hybrid polymer membranes are examined by scanning electron microscope (SEM). The intercalation of PVdF/PLS hybrid membranes is characterized by X-ray diffraction (XRD), differential scanning calorimeter (DSC) and thermal gravimetric analysis (TGA). The incorporation of PLS in PVdF matrix can enhance ionic conductivities and electrochemical stabilities for the prepared HMGPEs. The assembled lithium-ion batteries based on HMGPEs with weight ratio 80:20 of PVdF and PLS (PVdF/PLS-20) delivers the highest charge-discharge capacity (about 175mAh g~(-1)), and the cell based on HMGPEs of with weight ratio 90:10 of PVdF and PLS(PVdF/PLS-10) shows the best stability in cycle performance.