An investigation of ionic hydration effects in perfluorosulfonate ionomers by Fourier transform infrared spectroscopy

Lowry, S. R.; Mauritz, Kenneth A.

doi:10.1021/ja00534a017

Cited by 228 publications

(203 citation statements)

References 0 publications

Supporting

Mentioning

182

Contrasting

Unclassified

Order By: Relevance

“…31,32 Conversely, small inorganic ions such as lithium form strong electrostatic dipoles, which upon ionic aggregation yield strong electrostatic crosslinks. 31,33 Lowry et al 33 have reported that interactions of contact ion pairs between the sulfonate group and the smaller Li + ions become stronger in dehydrated perfluorosulfonate ionomers which, ultimately, induce polarization of the sulfonate group, consequently, the dissociation of the ion pair decreased. In addition, the difference of ionic conductivity between the TEA + -Nafion and the TBA + -Nafion can be related to the difference in the cation radii (r); r TEA+ = 0.39 nm and r TBA+ = 0.73 nm, respectively.…”

Section: Resultsmentioning

confidence: 99%

Performance of a Non-Aqueous Vanadium Acetylacetonate Prototype Redox Flow Battery: Examination of Separators and Capacity Decay

Escalante-García

Wainright

Thompson

et al. 2014

J. Electrochem. Soc.

126

118

View full text Add to dashboard Cite

Non-aqueous electrolytes are stable over wide electrochemical potential windows, generally >2 V, and therefore hold promise for enabling higher energy and power density redox flow batteries (RFBs). Nevertheless, the development of non-aqueous RFBs is at an early stage and significant research efforts are needed to demonstrate non-aqueous RFBs with performance characteristics that exceed those of aqueous RFBs. The membrane or separator is a critical component that to a great extent determines the performance of RFB systems for practical applications. In this work, the performance of a RFB was evaluated with Nafion 1035 membranes and Daramic 175 SLI microporous separators. The non-aqueous electrolyte was based on vanadium (III) acetylacetonate. This chemistry possesses two couples over ∼2.2 V. Charge-discharge cycles were performed in a RFB at a current density of 10 mA cm −2 . Coulombic and energy efficiencies of 91% and 80% were achieved using the Nafion membrane. A similar RFB using the Daramic microporous separator achieved columbic and energy efficiencies of 73% and 68%, respectively. The source of capacity decay during multiple charge-discharge cycles was also investigated. The loss in the capacity was related to the poor chemical stability of the vanadium acetylacetonate in the positive electrolyte during battery cycling. Redox flow batteries (RFBs) have emerged as very attractive options for large-scale energy storage applications and, could facilitate the integration of renewable energy resources (e.g. wind and solar) with the current electricity grid.1,2 RFBs are electrochemical devices that store electrical energy in soluble electro-active species in a liquid electrolyte. The electro-active species are stored externally in separate reservoirs and are pumped through the battery stack during operation. The energy is stored or delivered by means of a redox reaction between the two species with different standard electrode potentials, separated by a membrane.2,3 Unlike conventional batteries, RFBs are more attractive for large scale energy storage because they offer more flexible operation, simple electrode reactions, longer cycle life, higher overall energy efficiencies and easier scale-up. 4 Nonetheless, RFB technology is still in an early stage; challenges that remain in the quest to produce devices with high power and energy density at low cost include the discovery or development of stable, high energy density redox electrolytes, and efficient and low cost membranes or separators. 1,5 Aqueous and non-aqueous chemistries are being investigated for use in RFBs. The cell potential of aqueous RFBs is limited to less than ∼1.6 V primarily due to the electrochemical stability of water at carbon/graphite electrodes.6 Non-aqueous solvents, on the other hand, exhibit wider electrochemical potential windows, offering the possibility for higher power and energy densities. Several non-aqueous electrolytes using metal-ligand complexes as the active-redox species in organic solvents have exhibited cell potentials ab...

show abstract

Section: Resultsmentioning

confidence: 99%

Performance of a Non-Aqueous Vanadium Acetylacetonate Prototype Redox Flow Battery: Examination of Separators and Capacity Decay

Escalante-García

Wainright

Thompson

et al. 2014

J. Electrochem. Soc.

126

118

View full text Add to dashboard Cite

show abstract

“…In addition, the characteristic peaks of 1056 cm À1 and 970 cm À1 correspond to the symmetric stretching vibration of −SO 3 H and C-O-C in Na¯on. [20][21][22][23][24] XRD patterns of Na¯on, Pt-NF/C, and Pt/C catalysts are shown in Fig. 2(b).…”

Section: Resultsmentioning

confidence: 99%

Enhancing the Specific Activity of Metal Catalysts Toward Oxygen Reduction by Introducing Proton Conductor

Cheng

Liu

et al. 2016

NANO

View full text Add to dashboard Cite

Enhancing oxygen reduction reaction (ORR) activity and simultaneously reducing usage of noble metal catalysts are signi¯cantly important both in fundamental and applied science communities for polymer electrolyte fuel cells (PEFCs). In this work, we con¯rm the proton conductor (per-°u orosulfonic acid, containing ÀSO 3 H) can promote the speci¯c activity ðI s Þ of metal catalysts toward ORR. Herein, Pt nanoparticles (NPs) with a small and narrow size distribution are encapsulated with per°uorosulfonic acid through a simple colloidal route. The resulting catalyst obtains about two times ðI s Þ towards ORR than that of the pristine Pt/C. Signi¯cantly, the amount of ÀSO 3 H groups is controlled by a heat-treatment method to investigate the in°uence of ÀSO 3 H groups on ðI s Þ. The results evidence the contribution of ÀSO 3 H groups to elevating the ORR speci¯c activity. The mechanism can be ascribed to the ÀSO 3 H groups which e®ectively promote the transfer process of reaction species (e.g., H þ , H 2 O), improving the triple-phase boundary (TPB).

show abstract

“…As mentioned earlier, a cation in a fully hydrated Nafion  is in a dynamic equilibrium between bound and unbound states. [14][15][16] It was found not long ago that Ag + in the gel-type membranes coordinates to three oxygen atoms. 13 On the basis of these findings, it is probable that Ag + in a fully hydrated membrane alternately coordinates to oxygen atoms from water molecules and the sulfonate group.…”

Section: Resultsmentioning

confidence: 99%

“…[14][15][16] It was evident that the sulfonate groups in a fully hydrated membrane were shielded from the nearest counterion by several water molecules. Nevertheless, there was a dynamic equilibrium between strongly associated ion pairs and relatively free ions.…”

Section: Introductionmentioning

confidence: 99%

Untitled

Sungpet¹

2002

ScienceAsia

View full text Add to dashboard Cite

Ab initio calculations are done to explore the influence of water on the Ag + -C 2 H 4 complex formation. The simulated coordination environment of Ag ion is based on the existence of a dynamic equilibrium between the coordination of Ag ion with water and a sulfonate group, the counter ion. Calculated electronic properties reveal that electron delocalization from water molecules and the sulfonate group onto Ag 5s-atomic orbital reduces the ability of Ag ion to accept additional electrons from the C 2 H 4 π-orbital. The dissociation of water molecules from the hydrated Ag + is essential for the thermodynamic possibility of the Ag-C 2 H 4 complex formation. It is also evident from the electronic structure calculations that the dissociation of water is favorable for the formation of a stable Ag-C 2 H 4 complex. In the absence of water, the reaction between Ag ion strongly bound to sulfonate group and C 2 H 4 is thermodynamically impossible.

show abstract

An investigation of ionic hydration effects in perfluorosulfonate ionomers by Fourier transform infrared spectroscopy

Cited by 228 publications

References 0 publications

Performance of a Non-Aqueous Vanadium Acetylacetonate Prototype Redox Flow Battery: Examination of Separators and Capacity Decay

Performance of a Non-Aqueous Vanadium Acetylacetonate Prototype Redox Flow Battery: Examination of Separators and Capacity Decay

Enhancing the Specific Activity of Metal Catalysts Toward Oxygen Reduction by Introducing Proton Conductor

Untitled

Contact Info

Product

Resources

About