Preparation And Research On LCI/PEO-PMMA Blend Polymer Electrolytes

Polymer lithium-ion battery is widely used in small mobile devices, such as phones,laptops, etc. Compared with traditional liquid lithium-ion battery, polymer lithium batteryhas some advantages, such as higher energy、long cycle life、better security and designflexibility. Polymer electrolyte is the key decision material of polymer lithium battery.Now the polymer electrolyte also has some drawbacks，like low ionic conductivity、low iontransport number、poor mechanical strength and poor thermodynamic stability. Preliminarystudy found that PEO solid polymer electrolyte had poor conductivity at room temperature,although PMMA gel state polymer electrolyte has a good conductivity, the mechanicalproperties is too poor.PEO and PMMA blends were used as polymer electrolyte matrix in this paper. Inorder to improve the conductivity and mechanical properties of the polymer electrolyte, theliquid crystal ionomer （LCI） was added to the polymer electrolyte system. ThePEO-PMMA substrate, lithium per chlorate （LiClO₄） and LCI was prepared by solutioncasting method. Examined a total of three systems of the PEO-PMMA、PEO-PMMA-LiClO₄、 PEO-PMMA-LiClO₄-LCI. Used infrared spectroscopy、 ACimpedance、differential scanning calorimetry、scanning electron microscopy、polarizedlight microscopy to test the performance of the polymer electrolyte membrane.From the IR can be seen， there are Interaction between the PEO and PMMA straight.Due to the addition of LiClO₄，PEO peaks moved from1130cm^-1to1160cm^-1， explainedthat there is an interaction between PEO and Li+.The addition of LCI makes LiClO₄peaksmoved from3550cm^-1to3480cm^-1，explained that there is an interaction between LiClO₄and LCI. From the determination of electrical conductivity can be seen that，in thePEO-PMMA-LiClO₄series，With LiClO₄content increases, the conductivity increases.LiClO₄content reaches10%reached the maximum4.40E-04S/cm.In thePEO-PMMA-LiClO₄-LCI series，With LCI’s content increases, the conductivity firstincreases and then decreases. LCI content reaches1.0%reached the maximum2.53E-03S/cm. combination of infrared results can be shown that the addition of LCI canincrease the conductivity of the polymer. DSC can be seen pure PEO crystalline was 47.5%.With the addition of LiClO₄and LCI，the Least crystalline is9.21%.Because a lowdegree of crystallinity is more conducive to improve the ionic conductivity. Polarizingmicroscope also show that the addition of LCI can effectively reduce the degree ofcrystallinity of the polymer electrolyte.