J. Mater. Sci. Technol. ›› 2021, Vol. 69: 212-227.DOI: 10.1016/j.jmst.2020.08.032

• Invited Review • Previous Articles     Next Articles

An overview of amphoteric ion exchange membranes for vanadium redox flow batteries

Lei Liua,1, Chao Wanga,*(),1, Zhenfeng Heb, Rajib Dase,f, Binbin Dongd,*(), Xiaofeng Xiec,*(), Zhanhu Guoe,*()   

  1. a College of Materials Science and Engineering, North University of China, Taiyuan 030051, China
    b School of Chemical Engineering and Technology, North University of China, Taiyuan 030051, China
    c Institute of Nuclear and New Energy Technology, Tsinghua University, Beijing 100084, China
    d Key Laboratory of Materials Processing and Mold (Zhengzhou University), Ministry of Education, National Engineering Research Center for Advanced Polymer Processing Technology, Zhengzhou University, Zhengzhou 450052, China
    e Integrated Composites Laboratory (ICL), Department of Chemical & Biomolecular Engineering, University of Tennessee, Knoxville, TN 37996, USA
    f Oxea Chemical Company (OQ), Bay City, TX 77414, USA

Abstract:

Vanadium redox flow battery (VRB), as the most promising large-scale electrical energy storage units, has attracted extensive attention. Amphoteric ion exchange membrane (AIEM), as the core part of VRB, separates electrolyte on both sides of electrolytic tank and conducts H+. The AIEM with cation and anion groups possesses excellent performances, such as high ion conductivity (σ), low vanadium ion permeability (PVn+), relative stability and low cost. However, the performance of AIEM directly depends on the chemical structure of polymers. In addition to ensuring foundational physical performance, ion selectivity of AIEM is significant since the crossover of vanadium ion with various valences may reduce the battery capacity. In this paper, AIEMs for VRB and their chemical structures as well as synthesis approaches to realize all kinds of high-performing AIEMs are reviewed. The current trend and future direction of prospective materials for the VRB separators are documented in detail as well.

Key words: AIEMs, VRB, Proton conduction, Ion selectivity