Non-woven fabric supported poly(acrylonitrile-vinyl acetate) gel electrolyte for lithium ion battery use

This paper reported on a new gel polymer electrolyte (GPE) based on polyethylene (PE) non-woven fabric supported poly(acrylonitrile-vinyl acetate) (P(AN-VAc)/PE) membrane for lithium ion battery use. The preparation and performances of the P(AN-VAc)/PE membrane and its GPE based on 1 M LiPF₆ in dimethyl carbonate/diethylene carbonate/ethylene carbonate (1:1:1 in volume) were investigated with a comparison of the unsupported P(AN-VAc) membrane. It is found that the P(AN-VAc)/PE membrane shows better mechanical strength and pore structure for electrolyte uptake than the P(AN-VAc) membrane, and subsequently the GPE based on P(AN-VAc)/PE exhibits higher ionic conductivity and electrochemical stability on cathode than the GPE based on P(AN-VAc). With the support of the non-woven fabric, the ionic conductivity of the GPE at room temperature increases from 1.4 to 3.8 mS cm⁻¹, the oxidation decomposition potential of the GPE on a stainless steel is improved from 5.0 to 5.6 V (vs. Li/Li⁺). The mesocarbon microbeads (MCMB)/LiMn₂O₄ battery using P(AN-VAc)/PE as separator retains 94% of its initial discharge capacity after 100 cycles at C/2 rate, showing that the P(AN-VAc)/PE membrane is a possible alternative to the expensive separator for current liquid lithium ion battery.