Hydronium Ion Diffusion in Model Proton Exchange Membranes at Low Hydration: Insights from Ab Initio Molecular Dynamics

2021 ◽  
Author(s):  
Tamar Zelovich ◽  
Karen I Winey ◽  
Mark E Tuckerman
Keyword(s):  
Power Generation ◽  
Molecular Dynamics ◽  
Fuel Cell ◽  
Diffusion Process ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Ab Initio Molecular Dynamics ◽  
Ion Diffusion ◽  
Hydronium Ion ◽  
Efficient Power

Fuel-cell deployable proton exchange membranes (PEMs) are considered to be a promising technology for clean and efficient power generation. However, a fundamental atomistic understanding of the hydronium diffusion process in...

scholarly journals OH− and H3O+ Diffusion in Model AEMs and PEMs at Low Hydration: Insights from Ab Initio Molecular Dynamics

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 355
Author(s):  
Tamar Zelovich ◽  
Mark E. Tuckerman
Keyword(s):  
Molecular Dynamics ◽  
Fuel Cell ◽  
Ab Initio ◽  
Cost Effective ◽  
Clean Energy ◽  
Proton Exchange ◽  
Ab Initio Molecular Dynamics ◽  
Anion Exchange Membranes ◽  
Diffusion Mechanisms ◽  
Dynamics Simulations

Fuel cell-based anion-exchange membranes (AEMs) and proton exchange membranes (PEMs) are considered to have great potential as cost-effective, clean energy conversion devices. However, a fundamental atomistic understanding of the hydroxide and hydronium diffusion mechanisms in the AEM and PEM environment is an ongoing challenge. In this work, we aim to identify the fundamental atomistic steps governing hydroxide and hydronium transport phenomena. The motivation of this work lies in the fact that elucidating the key design differences between the hydroxide and hydronium diffusion mechanisms will play an important role in the discovery and determination of key design principles for the synthesis of new membrane materials with high ion conductivity for use in emerging fuel cell technologies. To this end, ab initio molecular dynamics simulations are presented to explore hydroxide and hydronium ion solvation complexes and diffusion mechanisms in the model AEM and PEM systems at low hydration in confined environments. We find that hydroxide diffusion in AEMs is mostly vehicular, while hydronium diffusion in model PEMs is structural. Furthermore, we find that the region between each pair of cations in AEMs creates a bottleneck for hydroxide diffusion, leading to a suppression of diffusivity, while the anions in PEMs become active participants in the hydronium diffusion, suggesting that the presence of the anions in model PEMs could potentially promote hydronium diffusion.

Maleimide: a potential building block for the design of proton exchange membranes studied by ab initio molecular dynamics simulations

RSC Advances ◽  
2015 ◽  
Vol 5 (98) ◽  
pp. 80220-80227 ◽  
Author(s):  
Xuejiao Li ◽  
Liuming Yan ◽  
Baohua Yue
Keyword(s):  
Molecular Dynamics ◽  
Solid State ◽  
Ab Initio ◽  
Molecular Dynamics Simulations ◽  
Building Block ◽  
Proton Transport ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Ab Initio Molecular Dynamics ◽  
Dynamics Simulations

Ab initio molecular dynamics (AIMD) simulations are applied to the study of proton transport in solid state maleimide.

scholarly journals Pore-Filled Proton-Exchange Membranes with Fluorinated Moiety for Fuel Cell Application

Energies ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4433
Author(s):  
Hyeon-Bee Song ◽  
Jong-Hyeok Park ◽  
Jin-Soo Park ◽  
Moon-Sung Kang
Keyword(s):  
Fuel Cell ◽  
Proton Exchange Membrane ◽  
Continuous Process ◽  
Oxidation Stability ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Cross Linking ◽  
Polymer Backbone ◽  
Transfer Resistance ◽  
Exchange Membrane

Proton-exchange membrane fuel cells (PEMFCs) are the heart of promising hydrogen-fueled electric vehicles, and should lower their price and further improve durability. Therefore, it is necessary to enhance the performances of the proton-exchange membrane (PEM), which is a key component of a PEMFC. In this study, novel pore-filled proton-exchange membranes (PFPEMs) were developed, in which a partially fluorinated ionomer with high cross-linking density is combined with a porous polytetrafluoroethylene (PTFE) substrate. By using a thin and tough porous PTFE substrate film, it was possible to easily fabricate a composite membrane possessing sufficient physical strength and low mass transfer resistance. Therefore, it was expected that the manufacturing method would be simple and suitable for a continuous process, thereby significantly reducing the membrane price. In addition, by using a tri-functional cross-linker, the cross-linking density was increased. The oxidation stability was greatly enhanced by introducing a fluorine moiety into the polymer backbone, and the compatibility with the perfluorinated ionomer binder was also improved. The prepared PFPEMs showed stable PEMFC performance (as maximum power density) equivalent to 72% of Nafion 212. It is noted that the conductivity of the PFPEMs corresponds to 58–63% of that of Nafion 212. Thus, it is expected that a higher fuel cell performance could be achieved when the membrane resistance is further lowered.

scholarly journals Miniaturized Ceramic-Based Microbial Fuel Cell for Efficient Power Generation From Urine and Stack Development

2018 ◽  
Vol 6 ◽  
Author(s):  
Iwona Gajda ◽  
Andrew Stinchcombe ◽  
Irene Merino-Jimenez ◽  
Grzegorz Pasternak ◽  
Daniel Sanchez-Herranz ◽  
...  
Keyword(s):  
Power Generation ◽  
Fuel Cell ◽  
Microbial Fuel Cell ◽  
Efficient Power

scholarly journals Design of Promising Green Cation-Exchange-Membranes-Based Sulfonated PVA and Doped with Nano Sulfated Zirconia for Direct Borohydride Fuel Cells

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4205
Author(s):  
Marwa H. Gouda ◽  
Noha A. Elessawy ◽  
Sami A. Al-Hussain ◽  
Arafat Toghan
Keyword(s):  
Fuel Cell ◽  
Sulfated Zirconia ◽  
Low Cost ◽  
Composite Membranes ◽  
Proton Exchange Membranes ◽  
Proton Exchange ◽  
Poly Vinyl Alcohol ◽  
Binary Polymer ◽  
Physicochemical Features ◽  
Direct Borohydride Fuel Cells

The direct borohydride fuel cell (DBFC) is a low-temperature fuel cell that requires the development of affordable price and efficient proton exchange membranes for commercial purposes. In this context, super-acidic sulfated zirconia (SO4ZrO2) was embedded into a cheap and environmentally friendly binary polymer blend, developed from poly(vinyl alcohol) (PVA) and iota carrageenan (IC). The percentage of SO4ZrO2 ranged between 1 and 7.5 wt.% in the polymeric matrix. The study findings revealed that the composite membranes’ physicochemical features improved by adding increasing amounts of SO4ZrO2. In addition, there was a decrease in the permeability and swelling ratio of the borohydride membranes as the SO4ZrO2 weight% increased. Interestingly, the power density increased to 76 mW cm−2 at 150 mA cm−2, with 7.5 wt.% SO4ZrO2, which is very close to that of Nafion117 (91 mW cm−2). This apparent selectivity, combined with the low cost of the eco-friendly fabricated membranes, points out that DBFC has promising future applications.

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