Pore-Size-Tuned Graphene Oxide Frameworks as Ion-Selective and Protective Layers on Hydrocarbon Membranes for Vanadium Redox-Flow Batteries

• DOI: 10.1021/acs.nanolett.8b01429
• Publication Date: 2018-05-03T22:45:58Z
• Authors: Soohyun Kim; Junghoon Choi; Chanyong Choi; Jiyun Heo; Dae Woo Kim; Jang Yong Lee; Young Taik Hong; Hee-Tae Jung; Hee-Tak Kim
• Keywords: Vanadium Oxide

The laminated structure of graphene oxide (GO) membranes provides exceptional ion-separation properties due to the regular interlayer spacing (d) between laminate layers. However, a larger effective pore size immersed in water (∼11.1 Å) than hydrated diameter vanadium ions (>6.0 prevents its use redox-flow batteries (VRFB). In this work, we report an ion-selective framework (GOF) with d tuned by cross-linking GO nanosheets. Its (∼5.9 excludes but allows proton conduction. GOF membrane is employed as protective layer address poor chemical stability sulfonated poly(arylene ether sulfone) (SPAES) against VO2+ VRFB. By effectively blocking ions, GOF/SPAES exhibits vanadium-ion permeability 4.2 times lower and durability 5 longer that pristine SPAES membrane. Moreover, VRFB achieves energy efficiency 89% at 80 mA cm–2 capacity retention 88% even after 400 cycles, far exceeding results for Nafion 115 demonstrating practical applicability