Humidity effect on electrical properties of layered α-zirconium phosphate

De, Sourya Joyee

doi:10.1016/j.ssc.2005.02.036

Cited by 2 publications

(2 citation statements)

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“…Different structural modifications of ZP have different types of proton diffusion paths, which affect the proton conductivity through the inorganic material framework. 31 In layered structures, the bulk diffusion of the hydronium ions occurs through the open cavities parallel to the layer, 36 but the mobility of the interior hydronium ions is about 10 4 times less than the mobility of the surface ͑ad-sorbed͒ hydronium ions, 37 because the free water molecules on a crystal surface can easily rotate and contribute to the ionic conduction by Grotthus mechanism. The rotation of hydronium ions in the interlayer spaces of ZP crystals is difficult due to strong hydrogen bonding with layered phosphate groups.…”

Section: Discussionmentioning

confidence: 99%

Nafion/Zirconium Phosphate Composite Membranes for PEMFC Operating at up to 120°C and down to 13% RH

Chalkova

Fedkin

Komarneni

et al. 2007

J. Electrochem. Soc.

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Nafion/zirconium phosphate ͑ZP͒ composite membranes of different structures containing in situ precipitated ZP, crystalline layer-structured ␣-zirconium hydrogen phosphate ␣-Zr͑HPO 4 ͒ 2 •H 2 O ͑␣-ZPL͒, and three-dimensional-network zirconium hydrogen phosphate H 3 OZr 2 ͑PO 4 ͒ 3 ͑ZPTD͒ were synthesized. The ZP materials used have different structure and surface properties ͑specific surface area, zeta potential, and particle morphology͒. The composite membranes were studied in an H 2 /O 2 proton exchange membrane fuel cell ͑PEMFC͒ over a range of relative humidity ͑RH͒ from 13 to 50% at temperatures of 80 and 120°C. At the operating temperature of 120°C, all studied composite membranes demonstrated significant improvement in performance under dehydrating conditions compared to unmodified Nafion membranes. Among the tested membranes, the Nafion/␣-ZPL composite membrane demonstrated the highest performance at 120°C at all RH values, especially at 13% RH. At 26 and 50% RH, the performance of Nafion/␣-ZPL and Nafion/19% ZP in situ membranes were close, and the performance of the Nafion/ZPTD membrane was the lowest. The effects of filled polymer pore constriction, scaffold formation, membrane structure, and surface properties of the ZP particles on the membrane performance in PEMFCs are discussed in the paper.

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Section: Discussionmentioning

confidence: 99%

Nafion/Zirconium Phosphate Composite Membranes for PEMFC Operating at up to 120°C and down to 13% RH

Chalkova

Fedkin

Komarneni

et al. 2007

J. Electrochem. Soc.

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“…Among these, Zr(HPO 4 ) 2 H 2 O (ZHP)-modified Nafion composite membranes have been studied extensively [43,[61][62][63][64][65][66][67][68][69][70][71][72][73][74][75][76][77][78]. Zirconium hydrogen phosphate and its derivatives feature high proton conductivity and good water retention [41], and are regarded as promising high temperature proton conductors [79].…”

Section: Introductionmentioning

confidence: 99%