Review Reports

Round 1

Reviewer 1 Report (Previous Reviewer 1)

Comments and Suggestions for Authors

his paper has been properly modified according to the reviewers' opinions.

Reviewer 2 Report (Previous Reviewer 2)

Comments and Suggestions for Authors

The additions made by the authors in yellow appear to be appropriate for publication.

Reviewer 3 Report (Previous Reviewer 4)

Comments and Suggestions for Authors

The revised manuscript has been improved. The quality of the figures, especially figure 2, should be improved before it publishes.

This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This paper is insufficiently written as a scientific paper; the discussion of L132-137 is not comprehensible from what is written. More detailed study of the mechanism by which graphite flakes and organo silicon gel suppress the volume expansion ratio is needed.
In addition, a detailed study of why the volume expansion ratio varies with the number of cycles in Figure 5 is necessary.

 

Reviewer 2 Report

Comments and Suggestions for Authors

REVIEW

1.       The term "V-Ti-Cr alloy" is essential to include in the abstract, introduction, conclusions, and accompanying references to emphasize its significance.

2.       Due to its importance, the term "Volume expansion" needs references to increase the reader's interest.

3.       The phrase "Metal hydride compact" should be included in the introduction, materials and methods, results and analysis, conclusions, and references. If applicable.

4.       The term "Organic silicone gel" should be included in the abstract, introduction, conclusions, and cited literature as a key word in this research work.

5.       It is essential to include more references on the topic of "Alloy Powders" to capture the interest of future readers.

6.       The term "hydrogen adsorption" is essential in this scientific article, so it is crucial to include relevant published literature in the references section.

7.       Some relevant discussion of the results from Figure 1 of “PCT curves of hydrogen desorption” needs to be included in the summary and conclusions.

8.       The XRD results presented in Figure 2 are not reported in the abstract and conclusions, so it is necessary to include them.

9.       The abstract and conclusions should include the findings obtained from "SEM and EDS analysis."

10.  This is before the conclusions, 3. Materials and Methods. It must be placed before the results and analysis section.

11.  The authors add a specific conclusion for each of figures 1 to 7 and a general conclusion to emphasize the work.

Comments on the Quality of English Language

An English correction always improves a paper, but it should be reviewed for the requested changes.

Reviewer 3 Report

Comments and Suggestions for Authors

This work reports on comparison of volume expansion of vanadium-based alloy powder and compacts during hydrogen sorption using a newly developed measurement system. The authors prepared the alloy powder and compacts from the V61Cr24Ti12Ce3 alloy synthesized using floating melting technology. The authors measured PCT curve of the alloy and evaluated the volume expansion behaviours of the alloy powder and compacts using the measurement system.

The results of these measurements indicated the following:

The volume expansion value of the powder bed was 131% for the initial hydrogen adsorption.

The values of the powder bed were 40-45% for the 2nd to 5th hydrogen adsorption cycles.

The volume expansion value of the compact bed was 97% for the initial hydrogen adsorption.

The values of the compact bed were 13-21% for the 2nd to 5th hydrogen adsorption cycles.

The compact bed showed smaller volume expansion than the powder bed.

This manuscript may be useful in the field of hydrogen storage alloys.

However, there is a lack of data disclosure on the loading amounts of alloy samples during hydrogen absorption tests and the amount of hydrogen absorbed and released during each cycle.

If it is claimed that the volume expansion of the compact is smaller than that of the powder, the loading amount of the powder and compacts, as well as the amount of released hydrogen should be taken into consideration.

 

My other comment shown below:

P.2, line 70.

It may be desirable to reverse the plus and minus signs of ΔH and ΔS values during the adsorption and desorption.

 

P. 4, line 111 Figure 4 (b), horizontal axis

0st, 2st, 3st, 4st and 5st may be fixed to 0^th, 2^nd, 3^rd, 4^th and 5^th respectively.

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript has been reviewed. The research topic is of great interest to the hydrogen community. However, the work itself needs to be improved for publish in the journal. The major disadvantage of the work is that it does not include enough data to demonstrate the scientific soundness of this topic. The experimental work only involves one sample for testing. It only presents the expansion result without scientific soundness. The reader will be interest in why the expansion happen, and what modifications of the material can reduce the expansion, etc. All of these requires more testing data to justify. 

The structure of the manuscript should be improved as well. The experimental section related to expansion measurement, including Figure 3, should put into a separate experimental section, instead of putting into results and discussion section.

One minor problem, the number of Figure 7 in the manuscript should be Figure 6.

Comments on the Quality of English Language

English is OK. Minor modifications are recommended.