Branched Sulfonated Polyimide/Sulfonated Methylcellulose Composite Membranes with Remarkable Proton Conductivity and Selectivity for Vanadium Redox Flow Batteries. Issue 4 (29th January 2020)

• Record Type: Journal Article
• Authors: Long, Jun; Yang, Hongyan; Wang, Yanlin; Xu, Wenjie; Liu, Jun; Luo, Huan; Li, Jinchao; Zhang, Yaping; Zhang, Hongping
• Is Part Of: ChemElectroChem. Volume 7:Issue 4(2020)
• Page Start: 937
• Page End: 945
• Publication Date: 2020-01-29
• Subjects: vanadium redox flow batteries -- branched sulfonated polyimide -- composite membrane -- proton conductivity -- cycling stability; Electrochemistry -- Periodicals; 541.37
• DOI: 10.1002/celc.201901887
• Languages: English
• ISSNs: 2196-0216

Abstract

Abstract: A series of branched sulfonated polyimide (bSPI)/sulfonated methylcellulose (s‐MC) composite membranes composed of a designed and synthesized bSPI polymer and functionalized s‐MC are prepared by using a facile solution casting method for vanadium redox flow batteries (VRFBs). Among all bSPI/s‐MC composite membranes, the optimized bSPI/s‐MC‐20 % composite membrane has the best proton selectivity of 2.45×10 5 S min cm −3, which is 14.4 times as high as the Nafion 115 membrane. The bSPI/s‐MC‐20 % composite membrane possesses superior proton conductivity compared to most reported SPI‐based composite membranes for VRFBs. The VRFB with a bSPI/s‐MC‐20 % composite membrane shows excellent battery efficiencies ( CE =99.2–98.0 %, EE =66.3–77.6 %) and capacity retention (73.3–47.2 %). Moreover, the cost of the bSPI/s‐MC‐20 % composite membrane is only a quarter of that of a commercial Nafion 115 membrane. This work develops a new strategy to fabricate cheap bSPI‐based composite membranes by introducing a suitable functionalized biomass material. Abstract : Branching out : A series of branched sulfonated polyimide (bSPI)/sulfonated methylcellulose (s‐MC) composite membranes are prepared for vanadium redox flow batteries (VRFBs). The cost of the bSPI/s‐MC‐20 % composite membrane is only a quarter of that of a commercial Nafion 115 membrane. Besides, a VRFB with the bSPI/s‐MC‐20 % composite membrane exhibits excellent battery efficiencies and cycling stability.