2022-06-02 オークリッジ国立研究所(ORNL)
Oak Ridge National Laboratory scientists are enhancing the performance of polymer materials for next-generation lithium batteries. Credit: Adam Malin/ORNL, U.S. Dept. of Energy
研究チームは、「充填物」を保護する硬い外層の間に導電性コアを挟み込んだブロック共重合体を設計した。この用途を想定した設計は、電解質を貫通して電池に損傷を与える可能性のあるリチウムの成長、樹状突起をブロックするようにナノエンジニアリングされている。
＜関連情報＞
- https://www.ornl.gov/news/polymers-better-battery-electrolytes
- https://iopscience.iop.org/article/10.1149/1945-7111/ac6a18
ナノ構造化ポリスチレン-PEO-ポリスチレントリブロック共重合体電解質におけるポリエチレンオキシド（PEO）ブロックの選択的可塑化 Selective Plasticization of Poly (ethylene oxide) (PEO) Block in Nanostructured Polystyrene− PEO− Polystyrene Triblock Copolymer Electrolytes
Guang Yang, Peng-Fei Cao, Ethan C. Self, Michelle Lehmann, Xi Chelsea Chen, Sheng Zhao, Sirui Ge, Chenhui Zhu, Tomonori Saito, Frank M. Delnick and Jagjit Nanda
Journal of The Electrochemical Society Published 4 May 2022
Abstract
The plasticization of a polymer electrolyte usually promotes its ionic conductivity but decreases its storage modulus due to the increased polymer chain flexibility. Herein, we show that such a tradeoff between the ionic conductivity and the mechanical robustness of the polymer electrolyte can be alleviated by selective plasticization of the ion-conductive block, such as poly(ethylene oxide) (PEO) in a polystyrene (PS)− PEO−PS block copolymer (SEO) electrolyte using an ether type plasticizer, tetraethylene glycol dimethyl ether (TEGDME). At maximum plasticizer loading, the room temperature ionic conductivity increases by up to 3 orders, whereas the storage modulus, G’ reduces to half, is still on the order of 102 MPa. At above the melting temperature of the PEO block, the dynamic storage modulus, G’ of the plasticized membrane surpasses its dry PS-PEO-PS counterpart. Such a phenomenon results from that, a) TEGDME co-crystallizes with PEO to promote its crystallinity and hence the storage modulus, b) TEGDME swells the amorphous PEO phase to enhance the polymer chain segmental mobility and hence ionic conductivity, and c) the PS phase remains intact from TEGDME to keep the SEO elastic.
