Conductive polyurethane elastomer electrolyte (PUEE) materials for anodic bonding

Haocheng Zhao; Weixuan Zhang; Xu Yin; Yuling Wu; Chao Du; Weigang Zhao; Li Zhao; Cuirong Liu

doi:10.1039/c9ra10944g

Conductive polyurethane elastomer electrolyte (PUEE) materials for anodic bonding

RSC Adv. 2020 Apr 1;10(22):13267-13276. doi: 10.1039/c9ra10944g. eCollection 2020 Mar 30.

Authors

Haocheng Zhao^{1

2}, Weixuan Zhang³, Xu Yin¹, Yuling Wu³, Chao Du¹, Weigang Zhao¹, Li Zhao^{1

2}, Cuirong Liu¹

Affiliations

¹ College of Materials Science and Engineering, Taiyuan University of Science and Technology Taiyuan 030024 China lcr@tyust.edu.cn.
² Department of Mechanical and Electrical Engineering, Shanxi Institute of Energy Jinzhong 030600 China.
³ Key Laboratory of Interface Science and Engineering in Advanced Materials, Taiyuan University of Technology Taiyuan 030024 China.

Abstract

Polyurethane elastomer electrolyte (PUEE) represents a promising class of polymer solid electrolytes for the preparation and packaging of flexible devices by anodic bonding. In this work, PUEEs were designed and prepared via a pre-polymerization method and cured at room temperature using polypropylene glycol (PPG), toluene-2,4-diisocyanate (TDI) and 1,4-butanediol (BDO) in the presence of varying amounts of lithium bis(trifluoromethanesulphonyl)imide (LiTFSI). All PUEEs exhibited high thermal stability and conductivity, with the highest ionic conductivity of 9.6 × 10^-5 S cm^-1 for PUEE6 (n _{[NHCOO]/Li⁺} = 1) at 55 °C. The results showed that LiTFSI was dissolved completely in the polyurethane matrix, and the complexing reactions occurred between the lithium ions and the polar groups of polyurethane. After that, the prepared PUEE and the Al sheet were successfully joined by the anodic bonding process. The microstructures of the bonded interface between PUEE and the Al sheet with a clear intermediate bonding layer could be observed in the cross-section scanning electron microscopy (SEM) images, and the elements in each layer were also detected by energy dispersive spectroscopy (EDS), which indicated that the PUEE and the Al sheet were bonded together. The maximum tensile strength for bonded PUEE6/Al was up to 0.45 MPa. All these results demonstrated that the prepared PUEE material would be a promising candidate for the preparation and packaging of flexible devices by anodic bonding.