Synthesis and electrochemical properties of poly(lithium 2-acrylamido-2-methylpropanesulfonate-co-vinyl triethoxysilane)-based interpenetrating network type single-ion conducting polymer gel electrolytes

A novel type of IPN single ion polymer gel electrolyte with high conductivity at room temperature as well as good chemical stability was synthesized by building double networks. One network was formed by the crosslinking monomer poly(etheylene glycol) dimethacrylate (PEGDMA) and monomer AMPEO, the other one was constructed by the synthesized copolymers P(LiAMPS-VTES) which provide the self-cross-linking ability due to containing Si-OEt groups as well as the ability of providing Li⁺. The electrolytes were characterized by means of surface morphology, element distribution, the ionic conductivity, lithium ion transference number, electrochemical stability and thermal stability. SEM images and EDX mappings indicated that two networks were entangled with each other due to the forced compatibility of IPN structure, so the two phases mutually penetrated between each other and the membrane was transparent. The ionic conductivity of polymer gel electrolyte was a function of the molar ratio of LiAMPS and was up to 6.23×10^-4 S ·cm^-1 at ambient temperature. The temperature dependence of the ionic conductivity followed the Arrhenius equation. Thermal analysis demonstrated that the decomposition temperature of polymer electrolytes was above 200 °C, which indicated that the thermal property of polymer electrolytes met the requirements of lithium-ion batteries. The cationic transport number was close to unity due to the suppression of the transport of the large counter polymeric anion. Electrochemical stability window of the polymer gel electrolyte reached 4 V versus Li.