V2O5-Activated Graphite Felt with Enhanced Activity for Vanadium Redox Flow Battery
Round 1
Reviewer 1 Report
The work is devoted to the study of new types of materials for lithium-ion batteries based on vanadium oxide. The authors have done significant experimental work with the involvement of a fairly large number of different research methods, which made it possible to characterize the synthesized structures with high accuracy. The article corresponds to the subject matter of the declared journal and can be published after answering the following questions that arose while reading it.
1. The results presented by the authors are impressive, but there is no data on the structural parameters of the samples under study obtained using X-ray diffraction methods.
2. Regarding the method of obtaining. The method used is quite interesting and highly efficient, but the authors should give an explanation of what is the reason for such a long annealing time.
3. Regarding the data on the hydrophobicity of the obtained samples, the authors should give a more detailed explanation of the data obtained, as well as what exactly caused such large values ​​of the contact angle of wetting.
4. The authors cite a fairly large number of structural parameters, but we would also like to see the data on changes in the porosity of the samples under study, and whether its measurements were carried out, since porosity plays not only an important role in the performance and stability of anode materials, but also on the degree of hydrophobicity.
5. Were the measurements of the morphological features of the synthesized samples after cyclic tests carried out? These experiments are necessary in order to assess the resistance of materials to corrosion and degradation processes after life tests.
Author Response
Please see the attachment
Author Response File: 
Author Response.pdf
Reviewer 2 Report
In this article, a new activation of graphite felt is presented for the positive half cell reaction in VRFB. The article is well organized, and the conclusions are sound. Here, some technical issues to take account in order to improve the manuscript.
- revise the whole manuscript since there are sentences very hard to follow. For example, -Compared with the grafting functional group and depositing electrocatalyst, etching the surface of GF can provide more pore and surface area for electrolyte flow and active site.
-Additionally, there some English corrections like : was oxidation during VO2 transfer to. Probably, the authors want to say that was oxidated….
- graphics are hard to follow. I recommend to the authors the implementation of bigger images and legends. For example, scale in Figure 2 is very hard to see.
- Introduce high SEM magnification in order to appreciate better the pores
- Since one precursor used was NH4VO3 , a N-functionalization is expected to introduce in the surface of GF. However, the authors focused the explanation on O-functionalities.
- Explain better the formation of the pores, especially the role of V2O5 and the possible functionalization of the graphite surface.
- The improvement of the charge and discharge (Figure 8) for the electrodes V3 and V10 is negligible in comparison with the improvement of TGF. Probably because, at those current densities the Hydrogen evolution reaction in negative compartment is quite important. Have the authors tested these electrodes in negative half-cell?
- Compare the results with the literature .
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have made all the corrections in the text of the article, the article can be accepted for publication.
