Investigation on polyethylene-supported and nano-SiO2 doped poly(methyl methacrylate-co-butyl acrylate) based gel polymer electrolyte for high voltage lithium ion battery

• P(MMA-co-BA)/nano-SiO2/PE based GPE was developed for high voltage lithium ion battery.
• P(MMA-co-BA)/nano-SiO2/PE has uniform and interconnected pore structure.
• The GPE exhibits improved ionic conductivity and compatibility with electrodes.
• 5 V battery using the GPE presents excellent cyclic stability.

Nano-SiO2 as dopant was used for preparing polyethylene-supported poly(methyl methacrylate-co-butyl acrylate) (P(MMA-co-BA)/PE) based membrane and corresponding gel polymer electrolyte (GPE), which is applied to improve the cyclic stability of high voltage lithium ion battery. P(MMA-co-BA)/nano-SiO2/PE based membranes and corresponding GPEs were characterized with scanning electron spectroscopy, X-ray diffraction, electrochemical impedance spectroscopy, mechanical test, thermogravimetric analysis, linear sweep voltammetry, and charge/discharge test. It is found that the GPE with 5 wt.% nano-SiO2 shows the best performance. Compared to the undoped membrane, the 5 wt.% nano-SiO2 doped membrane has a better pore structure and higher electrolyte uptake, leading to the enhancement in ionic conductivity of the resulting GPE from 1.23 × 10−3 to 2.26 × 10−3 S.cm−1 at room temperature. Furthermore, the thermal stability of the doped membrane is increased from 300 to 320 °C while its decomposition potential of GPE is from 5.0 to 5.6 V (vs. Li/Li+). The cyclic stability of Li/GPE/Li(Li0.13Ni0.30Mn0.57)O2 cell at the high voltage range of 3.5 V ∼ 5.0 V is consequently improved, the capacity retention of the cell using the doped membrane is 92.8% after 50 cycles while only 88.9% for the cell using undoped membrane and 66.9% for the cell using liquid electrolyte.