Browsing by Author "Cheng, Ming-Yao"

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A new graphene-modified protic ionic liquid-based composite membrane for solid polymer electrolytes
(2011)
Ye, Yun-Sheng
;
Tseng, Chi-Yung
;
Shen, Wei-Chung
;
Wang, Jing-Shiuan
;
Chen, Kuan-Jung
The production of a solid polymer electrolyte with high ionic conductivity and mechanical properties is the main fabrication challenge in application of polymer electrolyte membranes. This paper describes a novel polymer electrolyte membrane using protic ionic liquids (PILs) with ionic liquid polymer modified graphene (G) sheets [denoted PIL(NTFSI)-G] that exhibit dramatic enhancements in ionic conductivity (257.4%) and mechanical properties (345% improvement in tensile strength and a near 25-fold increase in modulus were achieved at 150 degrees C) with a minimal loading of PIL(NTFSI)-G (0.5 wt %). The addition of graphene, by sparing the high-cost PIL addition, gives a 20% cost-saving. The homogeneous distribution of graphene sheets as a 3D network through the polymer matrix in the composite membrane provides a high degree of continuous and interconnected transfer channels to facilitate ion transfer and enhance nanofiller-matrix adhesion to reinforce mechanical properties. This newly developed material provides a potential route toward the design and fabrication of polymer electrolytes.
Effect of morphology of mesoporous silica on characterization of protic ionic liquid-based composite membranes
(2011-07-01)
Ye, Yun-Sheng
;
Liang, Gao-Wei
;
Chen, Bo-Han
;
Shen, Wei-Chung
;
Tseng, Chi-Yung
Effects caused by the morphology of mesoporous silica on the characterization of protic ionic liquid-based composite membranes for anhydrous proton exchange membrane applications are investigated. Two types of SBA15 materials with platelet and fiberlike morphologies are synthesized and incorporated into a mixture of polymerizable monomers together with an ionic liquid (IL)[1-butyl-3-methylimidazolium bis(trifluoromethane sulfone)imide (BMIm-TFSI)] to form new conducting membranes using an in situ photo crosslinking process. Incorporation of a defined amount of fiber-shaped SBA 15 and platelet 15 significantly increases the ionic conductivity to between two and three times that of a plain poly(methyl methacrylate) (PMMA)/IL membrane (2.3 mS cm(-1)) at 160 degrees C. The protic ionic liquid (PIL) retention ability of the membranes is increased by the capillary forces introduced by the mesoporous silica materials, while ionic conductivity loss after leaching test is retarded. The highest ionic conductivity (5.3 mS cm(-1)) is obtained by incorporating 5 wt% of P-SBA 15 in the membrane to about six times that of plain PMMA/IL membrane (0.9 mS cm(-1)) at 160 degrees C after leaching test. (C) 2011 Elsevier B.V. All rights reserved.
Preparation and characterization of high-durability zwitterionic crosslinked proton exchange membranes
(2010-10-15)
Ye, Yun-Sheng
;
Chen, Wen-Yi
;
Huang, Yao-Jheng
;
Cheng, Ming-Yao
;
Yen, Ying-Chieh
The present present paper describes the development of a novel proton exchange membrane comprising a poly (styrene sulfonic acid-co-4-vinylpyridine) copolymer that was crosslinked with a haloalkyl crosslinker through the formation of ionic bonding linkages The nucleophilic substitution of these crosslinked membranes as well as a model reaction between pyridine and 1-bromobutane was confirmed by nuclear magnetic resonance (NMR) Tough and flexible membranes of a high mechanical strength were prepared. They demonstrated very elevated thermal, hydrolytic and oxidative stabilities as compared to other sulfonated polymers. The crosslinked membrane composed of zwitterionic molecules with a crosslinking fraction of 90.3, denoted SP-1, exhibited a proton conductivity of ca 7 1 x 10(-2) S cm(-1) at 30 degrees C under 90% relative humidity; a value comparable to that of Nafion 117 Moreover, the crosslinked SP-1 membrane possessed the highest selectivity for methanol fuel cells (3 38 x 10(5) S cm(-3) s), approximately five times that of Nafion 117. thus implying its potential for practical use in high-energy-density devices (C) 2010 Elsevier B.V All rights reserved.