Research Progress on Preparation Methods of Skutterudites

Round 1

Reviewer 1 Report

This is my review report of the manuscript entitled “Research Progress on Preparation Methods of Skutterudite Thermoelectric Materials” submitted by Chengyu Zhao, Minhua Wang, and Zhiyuan Liu for publication in the journal Inorganics (MDPI).

This article is a review paper dealing with the main experimental methods used to synthesize skutterudite materials, which are widely studied in academic research for their thermoelectric properties.

The text is clear and well written. The manuscript contains much useful information supported by 81 references to the scientific literature on the topic.

In my opinion, this is a valuable contribution of great interest to the readership of the journal Inorganics (MDPI). I recommend accepting this article for publication after considering the following minor points:

  - In the introduction, in the sentence "The Seebeck effect is used to realize the conversion of thermal energy and electric energy, …". Does it mean "the conversion of thermal energy into electric energy”?

   - Line 43, it would be relevant to move the references to the end of the sentence and to add "… figure of…" in the middle of the sentence "…the key is to improve the TE figure of merit ZT of materials [5-8]."

   - Lines 57 to 60, in the sentences "In the 1990s, Slack was the first …and the same high conductivity as crystals.". It is somewhat confusing to cite references that cite Slack and not Slack’s work itself. I recommend adding some Slack’s papers to the reference list.

   - Line 119, the word "relative" is used three times. This word is not scientifically accurate, even if "everything is relative". It would be better to remove it from this sentence and from the sentence in line 178.

   - Line 128, there is a symbol between "650℃" and "80 MPa". I don’t know what it is. Please check it and replace it. Same remark in line 205.

   - The resolutions of Figure 3 and Figure 6 should be improved.

Author Response

Response to comments on inorganics ID：1824823

Dear Reviewers and Editors,

    We would like to express our immense gratitude to you for your professional and valuable comments on our manuscript “Research Progress on Preparation Methods of Skutterudite Thermoelectric Materials”. We have carefully examined all the reviewer’s comments and the responses point by point are attached below. The manuscript has been revised according to the comments of the reviewers. The revisions in the new manuscript have been highlighted in red. If you have any queries to need our responses, please contact me directly at any time.

Responses to comments of Reviewer 1:

Comments:

This is my review report of the manuscript entitled “Research Progress on Preparation Methods of Skutterudite Thermoelectric Materials” submitted by Chengyu Zhao, Minhua Wang, and Zhiyuan Liu for publication in the journal Inorganics (MDPI).

This article is a review paper dealing with the main experimental methods used to synthesize skutterudite materials, which are widely studied in academic research for their thermoelectric properties.

The text is clear and well written. The manuscript contains much useful information supported by 81 references to the scientific literature on the topic.

In my opinion, this is a valuable contribution of great interest to the readership of the journal Inorganics (MDPI). I recommend accepting this article for publication after considering the following minor points:

1. In the introduction, in the sentence "The Seebeck effect is used to realize the conversion of thermal energy and electric energy, …". Does it mean "the conversion of thermal energy into electric energy”?

Reply: Thank you very much for your reminder. The statement in the original manuscript is not accurate, and it has been corrected in the revised manuscript. “Thermoelectric (TE) material is a kind of new energy functional material, which can directly convert electric energy and heat energy into each other using the Seebeck effect and Peltier effect”.

2. Line 43, it would be relevant to move the references to the end of the sentence and to add "… figure of…" in the middle of the sentence "…the key is to improve the TE figure of merit ZT of materials [5-8]."

Reply: Thank you very much for your reminder. Relevant references have been moved to the end of the sentence. The phrase "… figure of…" has been added in the middle of the sentence "…the key is to improve the TE merit ZT of materials [5-8]."

3. Lines 57 to 60, in the sentences "In the 1990s, Slack was the first …and the same high conductivity as crystals.". It is somewhat confusing to cite references that cite Slack and not Slack’s work itself. I recommend adding some Slack’s papers to the reference list.

Reply: Thank you very much for your reminder. The references cited in the original manuscript are incorrect, and the reference that slack proposed the concept of “phonon glass-electronic crystal” has been added in the revised manuscript.

4. Line 119, the word "relative" is used three times. This word is not scientifically accurate, even if "everything is relative". It would be better to remove it from this sentence and from the sentence in line 178.

Reply: Thank you very much for your suggestion. The word "relative or relatively " in some sentences in the revised manuscript has been deleted.

5. Line 128, there is a symbol between "650℃" and "80 MPa". I don’t know what it is. Please check it and replace it. Same remark in line 205.

Reply: Thank you very much for your reminder. This sentence has been revised in the new manuscript.

6. The resolutions of Figure 3 and Figure 6 should be improved.

Reply: Thank you very much for your valuable reminder. The resolutions of all figures in the manuscript have been improved to make them look clearer.

Author Response File: Author Response.docx

Reviewer 2 Report

The manuscript “Research Progress on Preparation Methods of Skutterudite Thermoelectric Materials “, by C. Zhao, M. Wang and Z. Liu is very interesting and to my knowledge the first one, which describes the most important methods (including examples) to prepare skutterudites for thermoelectric use and is therefore mostly suitable for publication. Yet, prior acceptance, it would be mostly appreciated if the authors could revise the following points:

1) The authors have probably overlooked a new, sustainable and fast preparation method, which not only is fast and therefore energy saving but also the skutterudites have high ZTs. In addition, it enables to produce samples in big quantities (50 g) and is therefore usable for industrial production. It is the method of severe plastic deformation, SPD, via high-pressure torsion, HPT. Bulks, gained via the solid-state reaction method (by the way, in our lab it does not take long) and manually ground or ball-milled or also commercial skutterudite powder can be densified in an HPT equipment within 15 minutes. As in the literature ZTs of higher than 2 for n-type and about 1.3 for p-type skutterudites are published, this new method must be added.

2) Generally, the manuscript is written in good English, however, the following should be corrected:

a) The authors use all variations of “skutterudite(s) thermoelectric material(s)”, which is not necessary (and” skutterudites thermoelectric material” is not correct), as it is enough to describe it once and then use “skutterudites” or “TE material” only in the text. For example instead of ….is one of the 162 traditional methods for the preparation of skutterudite TE material write: ….. is one of the 162 traditional methods for the preparation of skutterudites.

b) Please write “the TE figure of merit ZT” instead of “the TE merit ZT”

c) A sentence should never start with “however”, but connect 2 sentences. d) Please, do not use the word “technique” all the time, e.g. it is not necessary to write “by magnetron sputtering technique “, as “by magnetron sputtering“ is ok.

Author Response

Dear Reviewers and Editors,

    We would like to express our immense gratitude to you for your professional and valuable comments on our manuscript “Research Progress on Preparation Methods of Skutterudite Thermoelectric Materials”. We have carefully examined all the reviewer’s comments and the responses point by point are attached below. The manuscript has been revised according to the comments of the reviewers. The revisions in the new manuscript have been highlighted in red. If you have any queries to need our responses, please contact me directly at any time.

Responses to comments of Reviewer 2:

Comments:

The manuscript “Research Progress on Preparation Methods of Skutterudite Thermoelectric Materials “, by C. Zhao, M. Wang and Z. Liu is very interesting and to my knowledge the first one, which describes the most important methods (including examples) to prepare skutterudites for thermoelectric use and is therefore mostly suitable for publication. Yet, prior acceptance, it would be mostly appreciated if the authors could revise the following points:

1. The authors have probably overlooked a new, sustainable and fast preparation method, which not only is fast and therefore energy saving but also the skutterudites have high ZTs. In addition, it enables to produce samples in big quantities (50 g) and is therefore usable for industrial production. It is the method of severe plastic deformation, SPD, via high-pressure torsion, HPT. Bulks, gained via the solid-state reaction method (by the way, in our lab it does not take long) and manually ground or ball-milled or also commercial skutterudite powder can be densified in an HPT equipment within 15 minutes. As in the literature ZTs of higher than 2 for n-type and about 1.3 for p-type skutterudites are published, this new method must be added.

Reply: Thank you very much for your valuable reminder. The advanced preparation method (SPD-HPT) of your research group that you mentioned was indeed ignored in our original manuscript. This new preparation method is added in section 3.8 in the revised manuscript.

2. Generally, the manuscript is written in good English, however, the following should be corrected:

a) The authors use all variations of “skutterudite(s) thermoelectric material(s)”, which is not necessary (and” skutterudites thermoelectric material” is not correct), as it is enough to describe it once and then use “skutterudites” or “TE material” only in the text. For example instead of ….is one of the 162 traditional methods for the preparation of skutterudite TE material write: ….. is one of the 162 traditional methods for the preparation of skutterudites.

Reply: Thank you very much for your valuable reminder. The corresponding sentences in the manuscript have been modified and marked with red.

b) Please write instead of “the TE merit ZT”

Reply: Thank you very much for your valuable reminder. This phrase “the TE merit ZT” has been replaced by “the TE figure of merit ZT” in the revised manuscript.

c) A sentence should never start with “however”, but connect 2 sentences.

Reply: Thank you very much for your valuable reminder. The corresponding sentences in the manuscript have been modified and marked with red.

d) Please, do not use the word “technique” all the time, e.g. it is not necessary to write “by magnetron sputtering technique “, as “by magnetron sputtering“ is ok.

Reply: Thank you very much for your valuable reminder. The word “technique” after some preparation methods has been deleted in the revised manuscript.

Author Response File: Author Response.docx