Effect of interaction in allophane/PEO/LiClO₄ composite solid polymer electrolyte on crystallization of PEO

Abstract

In order to solve the safety problems in the lithium ion batteries used nowadays,the researchers were increasingly attracted by the solid electrolytes. Allophane was prepared from Na2SiO3 and AlCl3·6H2O by sol-gel method. By mixing the allophane and the polyethylene oxide/lithium perchlorate(PEO/LiClO4)with the solution blending method,the composite solid polymer electrolyte was obtained. X-ray diffraction(XRD),fourier transform infrared spectroscopy(FTIR),differential scanning calorimetry(DSC),transmission electron microscope(TEM),scanning electron microscope(SEM)and optical microscopy(OM)were used to characterize the microstructure and morphology of the samples. The results show that the noncovalent bonding interactions(complexation,hydrogen bonding,and Lewis acid-base interaction)among allophane,LiClO4 and PEO significantly inhibit the crystallization of PEO. The crystallinity of PEO decreases and then increases with the increase of allophone content. Moreover,the crystallinity of PEO decrease with the increase of LiClO4 content. When EO/Li+ molar ratio is 10:1 and the content of allophane is 5%(mass fraction),the crystallinity of PEO in the solid polymer electrolyte is only 4.12%.

Keywords

• allophane
• polyethylene oxide
• crystallization
• composite solid polymer electrolyte