title: Patents on Membranes Based on Non-Fluorinated Polymers for Vanadium Redox Flow Batteries.
abstract: BACKGROUND
  Vanadium redox flow batteries (VRFBs) have received considerable attention as large-scale electrochemical energy storage systems. In particular, VRFBs offer a higher power and energy density than other RFBs and mitigate undesirable performance fading, such as inevitable ion crossover, because of the unique advantage that only the vanadium ion is employed as the active species in the two electrolytes.
  
  
  METHODS
  The key constituent of VRFBs is a separator to conduct protons and prevent cross-mixing of the positive and negative electrolytes. For this purpose, ion exchange membranes like sulfonated polymer membranes can be used. Although this type of membrane does not have ion exchange groups, it can achieve an ion exchange capacity by the formation of pores.
  
  
  CONCLUSIONS
  This review highlights the patents on the preparation of non-fluorinated membranes (sulfonated aromatic polymer membranes and porous membranes) as alternatives to high-cost perfluorinated polymers and their VRFB performance.
authors: Department of Chemical Engineering, Kyonggi University, Yeongtong-gu, Suwon, Korea.|Research Center for Membrane, Korea Research Institute of Chemical Technology (KRICT), Yuseong-gu, Daejeon, Korea.
authors: So-Won
authors: SW
authors: Choi
authors: Research Center for Membrane, Korea Research Institute of Chemical Technology (KRICT), Yuseong-gu, Daejeon, Korea.
authors: Tae-Ho
authors: TH
authors: Kim
authors: Department of Chemical Engineering, Kyonggi University, Yeongtong-gu, Suwon, Korea.
authors: Sang-Ho
authors: SH
authors: Cha
keywords: Aromatic polymer; ion exchange membrane; non-fluorinated; separator; sulfonated polymer; vanadium redox flow
  battery.