Charge Carrier Molecular Sieve (CCMS) Membranes with Anti-aging Effect for Long-Life Vanadium Redox Flow Batteries

Abstract

Vanadium crossover hinders widespread commercial adoption of vanadium redox flow batteries (VRFBs). Superglassy polymers have the potential to offer high selectivity needed to control the crossover but as yet do not possess the requisite proton conductivity and stability. Here, we explore nanocomposite separators that can improve this selectivity. We report a dual-function charge carrier molecular sieve (CCMS) membrane, consisting of a high free volume microporous glassy polymer, poly[1-(trimethylsilyl)-1-propyne] (PTMSP)/sulfonated PAF (PAF-1-SO 3 H), that effectively hinders the migration of hydrated vanadium ions. Furthermore, ideally placed PAF-1-SO 3 H pores not only proved excellent for developing proton conductive channels but also suppressed physical aging within the separator. Experiments then linked this to an increased battery cycle life. As a consequence of achieving higher and more stable VRFB performance compared to benchmarked Nafion (Coulombic efficiencies of 97 vs 87% and capacity retention values of 85 vs 58% at a current density of 60 mA cm −2 , respectively), our integrated design heralds a class of stable separators for hydrogen-based energy technologies. KEYWORDS: super glassy polymer, sulfonated porous aromatic framework, thin-film composite mixed matrix membrane, charge carrier molecular sieve (CCMS) separator, H + /V 4+ selectivity, vanadium redox flow battery

An Ultra‐Low Self‐Discharge Aqueous|Organic Membraneless Battery with Minimized Br2 Cross‐Over

“…B) Capacity retention of 0.5 m Z|T, commercial Li‐ion, and Zn–Ni batteries at 90% SOC (independent repeat samples, Figure S7, Supporting Information), error bars represent mean ± standard deviation, n = 3 except for Day 120 Li‐ion and Day 0 Zn–Ni batteries ( n = 2). C) OCV retention comparison of 0.5 m Z|T at 90% SOC to 102 previously reported BLAMs [ 26–127 ] (with/without membrane, static/flow) at various SOCs corresponding to Table S1, Supporting Information.…”

Proton‐Conducting Polymers: Key to Next‐Generation Fuel Cells, Electrolyzers, Batteries, Actuators, and Sensors

“…For a study by Ghasemiestahbanati et al, a new membrane technology was developed to improve the lifespan and performance of VRFB. [63] The dual-function charge carrier molecular sieve (CCMS) membrane introduced in this research (Figure 10a), which was made from a combination of poly[1-(trimethylsilyl)-1-propyne] (PTMSP) and sulfonated porous aromatic framework (PAF-1-SO 3 H, Figure 10b), effectively enhanced the selectivity for hydrated vanadium ions and protons and suppressed physical aging within the separator (Figure 10c). The CCMS membrane successfully increased the Coulombic efficiency to 97 % and the capacity retention rate to 85 % at a current density of 60 mA cm À 2 .…”

Comprehensive Analysis of Critical Issues in All-Vanadium Redox Flow Battery

“…Singh et al 90 synthesized a cross-linked imidazole anion exchange membrane (AEM) by using an alkyl chain spacer, and the AEMs prepared by a crosslinked aliphatic polymer had good stable ionic conductivity and vanadium ion permeability resistance. Vanadium crossover has hindered the wide application of VRFBs, and Ghasemiestahbanati et al 91 developed a dual-function carrier molecular sieve membrane (CCMS), which effectively blocked the migration of hydrated vanadium ions. Although a variety of nonperfluorinated ion exchange membranes have been developed, their chemical stabilities are insufficient in the working environment of strong oxidation of VRFBs.…”