Pore-Scale Investigation of Mass Transport in Compressed Cathode Gas Diffusion Layer of Proton Exchange Membrane Fuel Cells

Round 1

Reviewer 1 Report

 

Comments and Suggestions for Authors

Dear Authors,

The Title:

 

 

 

 Pore-Scale Investigation of Mass Transport in Compressed Cathode Gas Diffusion Layer of Proton Exchange Membrane Fuel Cells

 

I have to read your manuscript with great attention and interest.

 

 

 

The authors examined the impact of additives introduced into the GDL on the operation of the low-temperature cell. As expected an increase in the volume fraction of the binder leads to the closure of the pores. As a result, mass transport losses increase.

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The submission falls within the scope of the journal and is sufficiently original. I recommended the publication after MINOR REVISIONS.

 

 

Specific comments:

• Keywords: I proposed the following change: Proton Exchange Membrane Fuel Cells (PEMFC), Gas diffusion layer (GDL), Lattice Boltzmann method; Compression; Binder; Mass transport
• The colors used in Fig. 8 do not correspond to the colors of the samples used in the previous charts

 

Author Response

Specific comments:

 

1. Keywords: I proposed the following change: Proton Exchange Membrane Fuel Cells (PEMFC), Gas diffusion layer (GDL), Lattice Boltzmann method; Compression; Binder; Mass transport

 

Response: Thank you for your comments, we have modified the keywords.

 

2. The colors used in Fig. 8 do not correspond to the colors of the samples used in the previous charts.

 

Response: Thank you for your comments. Figure 8 is inconsistent with what the previous chart was trying to represent, so we have used other colors, and the colors that have been used clearly distinguish the different samples, and we think it's reasonable to leave things as they are.

Reviewer 2 Report

In this paper, the authors present a study on mass transfer in the cathode layer of the proton exchange membrane of a fuel cell, during which a two-component LB model was developed.

However, while reading the work, I noticed the following shortcomings:

1) I think that in the introduction the authors should add more relevant references to the latest work in the field of fuel cells and prove the significance of the described research. 2) I think that the authors should add an explanation to the IP and TP thermal conductivity, since these concepts have not been introduced. 3) In my opinion, the authors should add an image schematically describing the principle of operation of the fuel cell under study in lines 121-124. 4) I think that the authors should add Figure 1 to the work immediately after its mention in the text and describe it in more detail. 5) Can the authors present photos of a slice of the GDL under study in their work? 6) In my opinion, the quality of the graphs needs to be improved.

Author Response

Comments:

 

1. I think that in the introduction the authors should add more relevant references to the latest work in the field of fuel cells and prove the significance of the described research.

Response: Thank you for your comments, we have added references to the latest relevant research in the field of fuel cells to the manuscript.

 

2. I think that the authors should add an explanation to the IP and TP thermal conductivity, since these concepts have not been introduced.

Response: Thank you for your comments. Numerous studies of the thermal conductivity of GDL have been carried out, however this is not the concern of this manuscript.

 

3. In my opinion, the authors should add an image schematically describing the principle of operation of the fuel cell under study in lines 121-124. 

Response: Thank you for your comments. However, in Section 2.1 we have given the computational domain and described the reactions that occur in the cathode electrode and the reactive gas transport.

 

4. I think that the authors should add Figure 1 to the work immediately after its mention in the text and describe it in more detail.

Response: Thank you for your comments. We have adjusted the position of Figure 1 in the manuscript.

5. Can the authors present photos of a slice of the GDL under study in their work?

Response: Thank you for your comments. Thank you for your input. The stochastic reconstruction method has been widely adopted for the reconstruction of PEMFC porous media, the advantage of which is that the structure of the GDL can be parametrically designed, and therefore the generated GDL is difficult to match with the structure of a specific GDL, and therefore it makes no sense to show a picture of the specific GDL.

6. In my opinion, the quality of the graphs needs to be improved.

Response: Thank you for your comments. All the figures are set at 600 dpi and inserted into WORD in uncompressed form. Your lack of clarity may be due to the fact that we have reduced the length of the sides of the figures for typesetting, and in fact, the quality of the images meets the needs of publication.

Reviewer 3 Report

In this paper, the authors reported the results of a simulation to control the microstructure of the gas diffusion layer through binder addition and compression to improve proton exchange membrane fuel cells (PEMFC) performance. Overall, no significant problems were found, and therefore, I think it will be possible to be published in "crystals" after minor revisions.

- If possible, the authors have to verify the validity of the proposed model by comparing the experimental and simulation results under specific conditions. - I'm also curious about whether the results of this model may vary depending on the type of binder materials, and please add an explanation about this to the text.

 

Author Response

Specific comments:

 

1. If possible, the authors have to verify the validity of the proposed model by comparing the experimental and simulation results under specific conditions.

Response: Thank you for your comments. Just as previous studies [1-3] conducted by scholars have established LB models that are compared with analytical solutions to verify the correctness of the models, the models in this manuscript have likewise been verified[4-5].

[1] Molaeimanesh G R, Akbari M H. A pore-scale model for the cathode electrode of a proton exchange membrane fuel cell by lattice Boltzmann method[J]. Korean Journal of Chemical Engineering, 2015, 32: 397-405.

[2] Chen L, Zhang R, Min T, et al. Pore-scale study of effects of macroscopic pores and their distributions on reactive transport in hierarchical porous media[J]. Chemical Engineering Journal, 2018, 349: 428-437.

[3] Chen L, Luan H B, He Y L, et al. Pore-scale flow and mass transport in gas diffusion layer of proton exchange membrane fuel cell with interdigitated flow fields[J]. International Journal of Thermal Sciences, 2012, 51: 132-144.

[4] Wang H, Yang G, Su F, et al. Cathode Electrochemical Performance of PEMFCs with Compressed Gas Diffusion Layer: A Pore-Scale Investigation[J]. Journal of The Electrochemical Society, 2022, 169(12): 124507.

[5] Yang G, Wang H, Su F, et al. Effect of porosity gradient in cathode gas diffusion layer on electrochemical performance of proton exchange membrane fuel cells[J]. Korean Journal of Chemical Engineering, 2023: 1-8.

2. - I'm also curious about whether the results of this model may vary depending on the type of binder materials, and please add an explanation about this to the text.

Response: Thank you for your comments. The material of the binder is usually the carbonized resin, which is reported in numerous literatures [6-9] and has been stated in the manuscript.

• Daino M M, Kandlikar S G. 3D phase-differentiated GDL microstructure generation with binder and PTFE distributions[J]. International Journal of Hydrogen Energy, 2012, 37(6): 5180-5189.
• Becker J, Flückiger R, Reum M, et al. Determination of material properties of gas diffusion layers: experiments and simulations using phase contrast tomographic microscopy[J]. Journal of The Electrochemical Society, 2009, 156(10): B1175.
• Thiedmann R, Fleischer F, Hartnig C, et al. Stochastic 3D modeling of the GDL structure in PEMFCs based on thin section detection[J]. Journal of the Electrochemical Society, 2008, 155(4): B391.
• Wang Y, Cho S, Thiedmann R, et al. Stochastic modeling and direct simulation of the diffusion media for polymer electrolyte fuel cells[J]. International journal of heat and mass transfer, 2010, 53(5-6): 1128-1138.