气候变化领域集成服务门户(CCPortal): Tuning the properties of poly(2,6-dimethyl-1,4-phenylene oxide) anion exchange membranes and their performance in H2/O2 fuel cells

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DOI	10.1039/c7ee02468a
	Tuning the properties of poly(2,6-dimethyl-1,4-phenylene oxide) anion exchange membranes and their performance in H2/O2 fuel cells
	Liu L.; Chu X.; Liao J.; Huang Y.; Li Y.; Ge Z.; Hickner M.A.; Li N.
发表日期	2018
ISSN	17545692
起始页码	435
结束页码	446
卷号	11 期号:2
英文摘要	Here, we present a complete investigation of poly(2,6-dimethyl-1,4-phenylene) (PPO) AEMs with quaternary ammonium (QA) groups placed at different locations within the chemical structure of the polymer, e.g. a standard benzyltrimethyl ammonium control (BTMA), side-chain-type (SCQA), long side-chain-type (LSCQA), comb-shaped (CQA), or side-chain type/comb-shaped (SCCQA) AEMs have been designed and studied. These copolymers possess a similar composition but considerably different molecular architectures, the nature of which significantly alters their properties and device performance. Hydroxide conductivity was improved for the SCQA, LSCQA and comb-shaped membranes possessing a C-18 alkyl terminal pendant compared to that of BTMA and comb-shaped samples with a short alkyl chain. In chemical stability experiments under 10 M NaOH and 80 °C for 200 hours, LSCQA and SCCQA samples with a C-18 alkyl terminal pendant architecture showed less decrease in conductivity (∼10%) than the BTMA, SCQA and SCCQA polymers having short alkyl chains, which lost more than 50% conductivity after alkaline stability testing. Significant degradation was observed for the unstable PPO AEM samples by either SN2 substitution or Hoffmann elimination according to 1H NMR analysis. Interestingly, the fuel cell device performance provided counterintuitive data that showed that longer side chains with excellent alkaline stability were not superior in device function assessment. Specifically, the highly alkaline stable long side-chain-type LSCQA-30 membrane showed significant degradation in a fuel cell device with an operating lifetime of 3.3 h at 100 mA cm-2. Analysis of the aged membrane showed SN2 substitution and elimination of trimethylamine to be the dominant degradation mechanisms. In contrast, the BTMA-30 membranes with poor alkaline stability showed good durability in a working device without obvious degradation after 8.3 h operation as confirmed by 1H NMR spectra. This new finding that contrasts membrane alkaline stability and device operation stability is extremely important and gives us directions for new polymer designs for high performance devices. Additionally, this study paves the way for coupled ex situ chemical stability and in-device degradation studies, which are sorely needed in this field. © 2018 The Royal Society of Chemistry.
英文关键词	Alkaline fuel cells; Alkalinity; Degradation; Fuel cells; Ion exchange membranes; Membranes; Nuclear magnetic resonance spectroscopy; Photodegradation; Polymers; Sodium hydroxide; Stability; Anion exchange membrane; Degradation mechanism; High performance devices; Hydroxide conductivities; Molecular architecture; Poly(2 , 6dimethyl-1 , 4-phenylene oxide); Quaternary ammonium; Structure of the polymers; Chemical stability; alkalinity; ammonium; degradation; experimental study; fuel cell; ion exchange; membrane; molecular analysis; oxide group; performance assessment; polymer
语种	英语
来源期刊	Energy & Environmental Science
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/190320
作者单位	State Key Laboratory of Coal Conversion, Institute of Coal Chemistry, Chinese Academy of Sciences, Taiyuan, 030001, China; University of Chinese Academy of Sciences, Beijing, 100039, China; Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo, 315201, China; Department of Materials Science and Engineering, Materials Research Institute, Pennsylvania State University, University Park, PA 16802, United States
推荐引用方式 GB/T 7714	Liu L.,Chu X.,Liao J.,et al. Tuning the properties of poly(2,6-dimethyl-1,4-phenylene oxide) anion exchange membranes and their performance in H2/O2 fuel cells[J],2018,11(2).
APA	Liu L..,Chu X..,Liao J..,Huang Y..,Li Y..,...&Li N..(2018).Tuning the properties of poly(2,6-dimethyl-1,4-phenylene oxide) anion exchange membranes and their performance in H2/O2 fuel cells.Energy & Environmental Science,11(2).
MLA	Liu L.,et al."Tuning the properties of poly(2,6-dimethyl-1,4-phenylene oxide) anion exchange membranes and their performance in H2/O2 fuel cells".Energy & Environmental Science 11.2(2018).