Highly proton conductive membranes based on carboxylated cellulose nanofibres and their performance in proton exchange membrane fuel cells

The performance of thin carboxylated cellulose nanofiber-based (CNF) membranes as proton exchange membranes in fuel cells has been measured in-situ as a function of CNF surface charge density (600 and 1550 µmol g-1), counterion (H+or Na+), membrane thickness and fuel cell relative humidity (RH 55 to 95 %). The structural evolution of the membranes as a function of RH, as measured by Small Angle X-ray scattering, shows that water channels are formed only above 75 % RH. The amount of absorbed water was shown to depend on the membrane surface charge and counter ions (Na+or H+). The high affinity of CNF for water and the high aspect ratio of the nanofibers, together with a well-defined and homogenous membrane structure, ensures a proton conductivity exceeding 1 mS cm-1at 30 °C between 65 and 95 % RH. This is two orders of magnitude larger than previously reported values for cellulose materials and only one order of magnitude lower than Nafion 212. Moreover, the CNF membranes are characterized by a lower hydrogen crossover than Nafion, despite being ≈ 30 % thinner. Thanks to their environmental compatibility and promising fuel cell performance the CNF membranes should be considered for new generation proton exchange membrane fuel cells.

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Highly proton conductive membranes based on carboxylated cellulose nanofibres and their performance in proton exchange membrane fuel cells

10.26434/chemrxiv.7851461 ◽

2019 ◽

Author(s):

Valentina Guccini ◽

Annika Carlson ◽

Shun Yu ◽

Göran Lindbergh ◽

Rakel Wreland Lindström ◽

...

Keyword(s):

Fuel Cells ◽

Fuel Cell ◽

Surface Charge ◽

Proton Exchange Membrane ◽

Membrane Surface ◽

Proton Exchange ◽

Membrane Thickness ◽

Fuel Cell Performance ◽

Cellulose Nanofibres ◽

Exchange Membrane

The performance of thin carboxylated cellulose nanofiber-based (CNF) membranes as proton exchange membranes in fuel cells has been measured in-situ as a function of CNF surface charge density (600 and 1550 µmol g-1), counterion (H+or Na+), membrane thickness and fuel cell relative humidity (RH 55 to 95 %). The structural evolution of the membranes as a function of RH, as measured by Small Angle X-ray scattering, shows that water channels are formed only above 75 % RH. The amount of absorbed water was shown to depend on the membrane surface charge and counter ions (Na+or H+). The high affinity of CNF for water and the high aspect ratio of the nanofibers, together with a well-defined and homogenous membrane structure, ensures a proton conductivity exceeding 1 mS cm-1at 30 °C between 65 and 95 % RH. This is two orders of magnitude larger than previously reported values for cellulose materials and only one order of magnitude lower than Nafion 212. Moreover, the CNF membranes are characterized by a lower hydrogen crossover than Nafion, despite being ≈ 30 % thinner. Thanks to their environmental compatibility and promising fuel cell performance the CNF membranes should be considered for new generation proton exchange membrane fuel cells.

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Proton Conductive Membranes Based on Carboxylated Cellulose Nanofibres and Their Proton Exchange Membrane Fuel Cell Performance

10.26434/chemrxiv.7851461.v2 ◽

2019 ◽

Author(s):

Valentina Guccini ◽

Annika Carlson ◽

Shun Yu ◽

Göran Lindbergh ◽

Rakel Wreland Lindström ◽

...

Keyword(s):

Fuel Cell ◽

Surface Charge ◽

Membrane Surface ◽

Cellulose Nanofibers ◽

Structural Evolution ◽

Proton Exchange ◽

Cell Performance ◽

Membrane Thickness ◽

Fuel Cell Performance ◽

Cellulose Nanofibres

The performance of carboxylated cellulose nanofibers (CNF) membranes has been measured in-situ as a function of CNF surface charge (600 and 1550 µmol g-1), membrane thickness and fuel cell relative humidity (RH 55 to 95 %). The structural evolution of the membrane as a function of RH has been measured by Small Angle X-ray scattering, showing that water channels are formed above 75 % RH. The amount of absorbed water depends on the membrane surface charge and counter ions (Na+ or H+). The high affinity of CNF for water and the high aspect ratio of the nanofibers, together with a well-defined and homogenous membrane structure, ensures a proton conductivity exciding 1 mS cm-1 at 30 °C between 65 and 95 % RH, around two orders of magnitude larger than previously reported values and only one order of magnitude lower than Nafion 212. Moreover, the CNF membranes are characterized by a lower hydrogen crossover than Nafion, despise been ≈ 30 % thinner. Thanks to their environmental compatibility and promising fuel cell performance the CNF membranes should be considered for new generation PEMFCs.

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A Numerical Investigation of Heat and Mass Transfer in Air-Cooled Proton Exchange Membrane Fuel Cells

Volume 2: Computational Fluid Dynamics ◽

10.1115/ajkfluids2019-5419 ◽

2019 ◽

Cited By ~ 1

Author(s):

Torsten Berning

Keyword(s):

Heat Transfer ◽

Fuel Cells ◽

Fuel Cell ◽

Proton Exchange Membrane ◽

Waste Heat ◽

Proton Exchange ◽

Fuel Cell Performance ◽

Air Stream ◽

Multi Phase ◽

Exchange Membrane

Abstract A numerical analysis of an air-cooled proton exchange membrane fuel cell (PEMFC) has been conducted. The model utilizes the Eulerian multi-phase approach to predict the occurrence and transport of liquid water inside the cell. It is assumed that all the waste heat must be carried out of the fuel cell with the excess air which leads to a strong temperature increase of the air stream. The results suggest that the performance of these fuel cells is limited by membrane overheating which is ultimately caused by the limited heat transfer to the laminar air stream. A proposed remedy is the placement of a turbulence grid before such a fuel cell stack to enhance the heat transfer and increase the fuel cell performance.

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Optimization of the Operating Parameters of a Proton Exchange Membrane Fuel Cell for Maximum Power Density

Journal of Fuel Cell Science and Technology ◽

10.1115/1.1867978 ◽

2005 ◽

Vol 2 (2) ◽

pp. 121-135 ◽

Cited By ~ 36

Author(s):

A. Mawardi ◽

F. Yang ◽

R. Pitchumani

Keyword(s):

Fuel Cells ◽

Fuel Cell ◽

Power Density ◽

Proton Exchange Membrane ◽

Proton Exchange ◽

Operating Conditions ◽

Optimum Operating ◽

Design Parameters ◽

Membrane Thickness ◽

Exchange Membrane

The performance of fuel cells can be significantly improved by using optimum operating conditions that maximize the power density subject to constraints. Despite its significance, relatively scant work is reported in the open literature on the model-assisted optimization of fuel cells. In this paper, a methodology for model-based optimization is presented by considering a one-dimensional nonisothermal description of a fuel cell operating on reformate feed. The numerical model is coupled with a continuous search simulated annealing optimization scheme to determine the optimum solutions for selected process constraints. Optimization results are presented over a range of fuel cell design parameters to assess the effects of membrane thickness, electrode thickness, constraint values, and CO concentration on the optimum operating conditions.

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Influence of the Nafion agglomerate morphology on the water-uptake behavior and fuel cell performance in the proton exchange membrane fuel cells

Applied Surface Science ◽

10.1016/j.apsusc.2019.03.113 ◽

2019 ◽

Vol 481 ◽

pp. 777-784 ◽

Cited By ~ 5

Author(s):

Tae-Hyun Kim ◽

Jung Hun Yoo ◽

T. Maiyalagan ◽

Sung-Chul Yi

Keyword(s):

Fuel Cells ◽

Fuel Cell ◽

Water Uptake ◽

Proton Exchange Membrane ◽

Proton Exchange ◽

Cell Performance ◽

Fuel Cell Performance ◽

Exchange Membrane

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Fuel cell performance of membrane electrode assembly with PDAC/sPPO self-assembly layer containing Pt-Ru catalyst on proton exchange membrane surface

Catalysis Today ◽

10.1016/j.cattod.2016.04.015 ◽

2016 ◽

Vol 278 ◽

pp. 237-246 ◽

Cited By ~ 3

Author(s):

Chieh-Hao Wan ◽

Nai-Chien Shih ◽

Yan Zhang Su ◽

Yu Chun Chiu

Keyword(s):

Fuel Cell ◽

Self Assembly ◽

Proton Exchange Membrane ◽

Membrane Surface ◽

Membrane Electrode Assembly ◽

Proton Exchange ◽

Membrane Electrode ◽

Fuel Cell Performance ◽

Ru Catalyst ◽

Exchange Membrane

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Active Water Management for Proton Exchange Membrane Fuel Cells Using an Integrated Electroosmotic Pump

Advanced Energy Systems ◽

10.1115/imece2005-79728 ◽

2005 ◽

Cited By ~ 1

Author(s):

Cullen R. Buie ◽

Jonathan D. Posner ◽

Tibor Fabian ◽

Suk-Won Cha ◽

Fritz B. Prinz ◽

...

Keyword(s):

Water Management ◽

Fuel Cells ◽

Fuel Cell ◽

Proton Exchange Membrane ◽

High Efficiency ◽

Proton Exchange ◽

Flow Rates ◽

Fuel Cell Performance ◽

Wide Range ◽

Exchange Membrane

We have developed proton exchange membrane fuel cells (PEMFC’s) with integrated planar electroosmotic pumping structures that actively remove liquid water from cathode flow channels. Recent experimental and numerical investigations on PEMFC’s emphasize water management as a critical factor in the design of robust, high efficiency fuel cells. Although various passive water management strategies have been proposed, water is still typically removed by pumping air into cathode channels at flow rates significantly larger than those required by fuel cell stoichiometry. This method of water removal is thermodynamically unfavorable and constrains cathode flow channel design. EO pumps can relieve cathode design barriers and simplify water management in fuel cells. EO pumps have no moving parts, scale across a wide range of operation, and result in low parasitic power. We demonstrate and quantify the efficacy of EO water pumping using a single-pass fuel cell test channel. Our results show that removing water from the cathode using integrated EO pumping structures improves fuel cell performance and stability. These pumps enable operation with air flow rates of just two to three times stoichiometric requirements.

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Theoretical Energy and Exergy Analyses of Proton Exchange Membrane Fuel Cell by Computer Simulation

Journal of Applied Chemistry ◽

10.1155/2016/2684919 ◽

2016 ◽

Vol 2016 ◽

pp. 1-15 ◽

Cited By ~ 11

Author(s):

I. D. Gimba ◽

A. S. Abdulkareem ◽

A. Jimoh ◽

A. S. Afolabi

Keyword(s):

Fuel Cell ◽

Proton Exchange Membrane ◽

Proton Exchange ◽

Cell Performance ◽

Membrane Thickness ◽

Operating Pressure ◽

Flow Rates ◽

Fuel Cell Performance ◽

Energy And Exergy ◽

Exchange Membrane

A mathematical model of a proton exchange membrane fuel cell (PEMFC) was developed to investigate the effects of operating parameters such as temperature, anode and cathode pressures, reactants flow rates, membrane thickness, and humidity on the performance of the modelled fuel cell. The developed model consisted of electrochemical, heat energy and exergy components which were later simulated using a computer programme. The simulated model for the voltage output of the cell showed good conformity to the experimental results sourced from the literature and revealed that the operating pressure, temperature, and flow rate of the reactants positively affect the performance and efficiencies (energy and exergy) of the cell. The results also indicated that high membrane thickness above 150 μm is unfavourable to both the fuel cell performance and the cell energy and exergy efficiencies. The simulated results obtained on the influence of membrane humidity on the cell performance indicated that membrane humidity positively favours both the performance and energy and exergy efficiencies of the cell. It can therefore be inferred that the performance of the PEMFC and energy and exergy efficiencies of the cell are greatly influenced by the operating pressure, temperature, membrane thickness, membrane humidity, and the flow rates of fuel and oxidant.

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