Covalent organic frameworks with flexible side chains in hybrid PEMs enable highly efficient proton conductivity

Ziwen Liu; Xiao Pang; Benbing Shi; Na Xing; Yawei Liu; Bohui Lyu; Leilang Zhang; Yan Kong; Sijia Wang; Zhong Gao; Rou Xue; Tianyu Jing; Changkun Liu; Qinhuidan Bai; Hong Wu; Zhongyi Jiang

doi:10.1039/d3mh01604h

Covalent organic frameworks with flexible side chains in hybrid PEMs enable highly efficient proton conductivity

Mater Horiz. 2024 Jan 2;11(1):141-150. doi: 10.1039/d3mh01604h.

Authors

Ziwen Liu^{1

2}, Xiao Pang^{1

2}, Benbing Shi^{1

2}, Na Xing^{1

2}, Yawei Liu³, Bohui Lyu^{1

2}, Leilang Zhang^{1

2}, Yan Kong^{1

2}, Sijia Wang^{1

2}, Zhong Gao^{1

2}, Rou Xue^{1

2}, Tianyu Jing^{1

2}, Changkun Liu^{1

2}, Qinhuidan Bai^{1

2}, Hong Wu^{1

2}, Zhongyi Jiang^{1

2

4}

Affiliations

¹ Key Laboratory for Green Chemical Technology of Ministry of Education, School of Chemical Engineering and Technology, Tianjin University, Tianjin 300072, China. wuhong@tju.edu.cn.
² Haihe Lab Sustainable Chem Transformations, Tianjin 300192, P. R. China.
³ Beijing Key Laboratory of Ionic Liquids Clean Process, CAS Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, 100190, China.
⁴ Joint School of National University of Singapore and Tianjin University, International Campus of Tianjin University, Binhai New City, Fuzhou, 350207, China.

PMID: 37916392
DOI: 10.1039/d3mh01604h

Abstract

Electrochemical hydrogen compression (EHC) is an emerging energy conversion technology. Proton exchange membranes (PEMs) with high proton conductivity and high mechanical strength are highly required to meet the practical requirements of EHC. Herein, ionic covalent organic frameworks (iCOFs) with tunable side chains were synthesized and introduced into the sulfonated poly (ether ether ketone) (SPEEK) matrix to fabricate hybrid PEMs. In our membranes, the rigid iCOFs afford ordered proton conduction channels, whereas the flexible side chains on iCOFs afford abundant proton conduction sites, adaptive hydrogen bonding networks, and high local density short hydrogen bonds for highly efficient proton transport. Moreover, the hydrogen bond interactions between the side chains on iCOFs and the SPEEK matrix enhance the mechanical stability of membranes. As a result, the hybrid PEM acquires an enhanced proton conductivity of 540.4 mS cm^-1 (80 °C, 100%RH), a high mechanical strength of 120.41 MPa, and a superior performance (2.3 MPa at 30 °C, 100%RH) in EHC applications.