Jung, Mina Lee, Wonmi Krishnan, N. Nambi Kim, Sangwon Gupta, Gaurav Komsiyska, Lidiya Harms, Corinna Kwon, Yongchai Henkensmeier, Dirk 2024-01-19T22:04:15Z 2024-01-19T22:04:15Z 2021-09-03 2018-08 0169-4332 https://pubs.kist.re.kr/handle/201004/121116 Although Nafion membranes have a high chemical stability against VO2+ and a low resistance, their low coulomb efficiency (CE), due to crossover of vanadium cations, should be addressed. PBI membranes are chemically stable and effectively block vanadium cations, but have a lower conductivity than Nafion. Here we describe the fabrication of layered membranes, which consist of a 40 mm thick porous Nafion layer and a 2-17 mu m thin PBI blocking layer. To promote adhesion, a <2 mu m thick layer of a 1:1 Nafion/ PBI blend is introduced between the outer layers. While this bonding layer is necessary to promote adhesion, the strong ionic interactions between Nafion and PBI reduce the acid uptake. Immersed in 1 M sulfuric acid (SA), the weight of meta-PBI increases 17%, while that of NP1:3, NP1:1 and NP3:1 only increases 16%, 8% and 7%, respectively. This decreases the conductivity in 2 M SA from 2.8 mS cm (1) for meta-PBI to 1.5, 0.4 and 0.04 mS cm (1) for NP1:3, NP1:1 and NP3:1, respectively. The initial CE of a flow battery using p-Nafion-1:1-PBI20 was as good as one with Nafion 212 (93% at 80 mA cm (2)), while one with p-Nafion-1:3-PBI3 showed exactly the same voltage efficiency as one with Nafion 212. (C) 2018 Elsevier B.V. All rights reserved. English ELSEVIER Porous-Nafion/PBI composite membranes and Nafion/PBI blend membranes for vanadium redox flow batteries Article 10.1016/j.apsusc.2018.04.198 1 APPLIED SURFACE SCIENCE, v.450, pp.301 - 311 APPLIED SURFACE SCIENCE 450 301 311 N scie scopus 000433199000035 2-s2.0-85046169679 Chemistry, Physical Materials Science, Coatings & Films Physics, Applied Physics, Condensed Matter Chemistry Materials Science Physics Article POLYBENZIMIDAZOLE MEMBRANES CELL APPLICATIONS THERMAL-BEHAVIOR PERFORMANCE STABILITY ELECTROLYTE SELECTIVITY NAFION(R) IONOMER PBI Vanadium redox flow battery (VRFB) Porous membrane Thin blocking layer Polybenzimidazole (PBI) Nafion