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

Nano-SiO 2 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-SiO 2 /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-SiO 2 shows the best performance. Compared to the undoped membrane, the 5   wt.% nano-SiO 2 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(Li 0.13 Ni 0.30 Mn 0.57 )O 2 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.