Supramolecular Functionalities Influence the Thermal Properties, Interactions and Conductivity Behavior of Poly(ethylene glycol)/LiAsF6 Blends

• Main Authors: Shiao-Wei Kuo, Chih-Chia Cheng, Feng-Chih Chang, Oleksii Altukhov, Jui-Hsu Wang
• Format: Article
• Language: English
• Published: MDPI AG 2013-07-01
• Series: Polymers
• Subjects: supramolecular structure; multiple hydrogen bonding; polymer electrolytes
• Online Access: http://www.mdpi.com/2073-4360/5/3/937

In this study, we tethered terminal uracil groups onto short-chain poly(ethylene glycol) (PEG) to form the polymers, uracil (U)-PEG and U-PEG-U. Through AC impedance measurements, we found that the conductivities of these polymers increased upon increasing the content of the lithium salt, LiAsF6, until the Li-to-PEG ratio reached 1:4, with the conductivities of the LiAsF6/U-PEG blends being greater than those of the LiAsF6/U-PEG-U blends. The ionic conductivity of the LiAsF6/U-PEG system reached as high as 7.81 × 10−4 S/cm at 30 °C. Differential scanning calorimetry, wide-angle X-ray scattering, 7Li nuclear magnetic resonance spectroscopy and Fourier transform infrared spectroscopy revealed that the presence of the uracil groups in the solid state electrolytes had a critical role in tuning the glass transition temperatures and facilitating the transfer of Li+ ions.