Polypropylene-supported and nano-Al2O3 doped poly(ethylene oxide)–poly(vinylidene fluoride-hexafluoropropylene)-based gel electrolyte for lithium ion batteries

A new gel polymer electrolyte (GPE) is reported in this paper. In this GPE, blending polymer of poly(ethylene oxide) (PEO) with poly(vinylidene fluoride-hexafluoropropylene) (P(VdF-HFP)), doped with nano-Al2O3 and supported by polypropylene (PP), is used as polymer matrix, namely PEO–P(VdF-HFP)–Al2O3/PP. The performances of the PEO–P(VdF-HFP)–Al2O3/PP membrane and the corresponding GPE are characterized with mechanical test, CA, EIS, TGA and charge–discharge test. It is found that the performances of the membrane and the GPE depend to a great extent on the content of doped nano-Al2O3. With doping 10 wt.% nano-Al2O3 in PEO–P(VdF-HFP), the mechanical strength from 9.3 MPa to 14.3 MPa, the porosity of the membrane increases from 42% to 49%, the electrolyte uptake from 176% to 273%, the thermal decomposition temperature from 225 °C to 355 °C, and the ionic conductivity of corresponding GPE is improved from 2.7 × 10−3 S cm−1 to 3.8 × 10−3 S cm−1. The lithium ion battery using this GPE exhibits good rate and cycle performances.