Separator Materials for Lithium Sulfur Battery—A Review

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Lithium Sulfur battery is a very interesting field. Separator materials play important role inside. This review is appropriate and valued.

Couple of comments to strengthen the manuscript.   

 1. There are much work related to mixing Sulphur, carbon material, metal oxide, etc. Please comment on the different ways of mixture and battery performance.

2. Suggest to add the below reference:

  A novel approach to fabricate carbon nanomaterials–nanoparticle solids through aqueous solutions and their applications

H Younes, H Hong, GP Peterson Nanomanufacturing and Metrology, 1-11, 2021   It provides the efficient way to disperse particle in the nano scale.

 3. Some errors in the English.

 

Comments on the Quality of English Language

Okay, but needs to improve.

Author Response

Green Science Alliance Co. Ltd

2-22-11 Obana Kawanishi-city, Hyogo prefecture 666-0015 JAPAN

 

                                                                                                                     

                                                                     October 23 2023

 

Editor in Chief and Reviewer 1

Electrochem

 

Dear Editor in Chief

 

Please find the revised manuscript “Separator Materials for Lithium Sulfur Battery – A Review” which I respectfully resubmit for consideration for publication in “Electrochem”.  I am most grateful to the editor and reviewers whose comments have helped to produce an improved manuscript.

 

 

Sincerely yours,

 

Ryohei Mori

 

************************************

Dr. Ryohei Mori

Green Science Alliance Co. Ltd

(Fuji Pigment Co., Ltd. Group)

2-22-11 Obana Kawanishi-city,

Hyogo Pref. 666-0015 JAPAN

TEL : +81-72-759-8501

FAX : +81-72-759-9008

mail:moriryohei@fuji-pigment.co.jp

WEB : http://www.fuji-pigment.co.jp/

************************************
Reviewer : 1

 

Comments to the Author

 

1. There are much work related to mixing Sulphur, carbon material, metal oxide, etc. Please comment on the different ways of mixture and battery performance.

 

Thank you for referee’s comment and I have added following explanations and references at introduction section. 

 

Even though, since sulfur as active material is essentially an electrically insulator so that it needs to be encapsulated in a conductive carbon matrix to provide appropriate electronic contact.  Furthermore, it is necessary to provide ionic pathways through the entire cathode, to assure the conversion reaction between the sulfur and lithium ions. Thus, intimate contact and particle distribution among the carbon, sulfur and additives, is the critical factor.  On top of that, the practical slurry manufacturing for actual pouch cell mass production are still challenging.  In this regard, Kaskel et al. introduced ball milling procedure for a scalable preparation method in order to achieve high sulfur utilization and loading³¹.  They have clarified carbon/sulfur agglomeration breakdown, decreasing particle size, suitable pore size volume and distribution which resulted in enhancing carbon/sulfur composite electrical conductivity as well as obtaining higher electrochemical performance. Similar studies of improved electrochemical performance by introducing high energy ball milling method, can be found in some other literatures^32,33.

 

2. Suggest to add the below reference:

 

A novel approach to fabricate carbon nanomaterials–nanoparticle solids through aqueous solutions and their applications

 

H Younes, H Hong, GP Peterson Nanomanufacturing and Metrology, 1-11, 2021   It provides the efficient way to disperse particle in the nano scale.

 

Thank you for referee’s comment and I have added following explanations and references at introduction section. 

 

Younes also had investigated the aggregation process between carbon nanomaterials and metal oxide particles, and improved the dispersion status in aqueous solutions³⁴. 

 

3. Some errors in the English.

 

Thank you to referee’s comment and I corrected several points of English error as it was also pointed out by another referee.  It is shown in the red letter in the revised article.

 

 

 

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The author summarized in this manuscript various functional seperators reported in literature. The manuscript is informative and well organized. This reviewer reccomends accept the manuscript as is. 

One minor request is that a list of contents would help potential readers to find specific topic quickly.

Author Response

Green Science Alliance Co. Ltd

2-22-11 Obana Kawanishi-city, Hyogo prefecture 666-0015 JAPAN

 

                                                                                                                             

 

                                                                     October 23 2023

 

Editor in Chief

Electrochem

 

Dear Editor in Chief and Reviewer 2

 

Please find the revised manuscript “Separator Materials for Lithium Sulfur Battery – A Review” which I respectfully resubmit for consideration for publication in “Electrochem”.  I am most grateful to the editor and reviewers whose comments have helped to produce an improved manuscript.

 

 

Sincerely yours,

 

Ryohei Mori

 

************************************

Dr. Ryohei Mori

Green Science Alliance Co. Ltd

(Fuji Pigment Co., Ltd. Group)

2-22-11 Obana Kawanishi-city,

Hyogo Pref. 666-0015 JAPAN

TEL : +81-72-759-8501

FAX : +81-72-759-9008

mail:moriryohei@fuji-pigment.co.jp

WEB : http://www.fuji-pigment.co.jp/

************************************

 

 

Reviewer : 2

Comments to the Author

 

One minor request is that a list of contents would help potential readers to find specific topic quickly.

Thank you for referee’s comment and I added following explanation and the list of contents, at the end of introduction section.

 

Separator materials we have selected in this review are the followings

2.1. Separator Material facing Anode Side

 

2.1.1.Metal

2.1.2. Ceramic

2.1.3. Solid Electrolyte

2.1.4. Other Functional Separator Materials

 

2.2. Separator Material facing Cathode Side

2.2.5. Carbonaceous Materials

2.2.6. Metal Oxide

2.2.7.     Metal Sulfide

2.2.8.     Metal Carbide

2.2.9.     Nitride

2.2.10.   Phosphide

2.2.11.   Metal Organic Framework-based Materials

2.2.12.   Quantum Dot

2.2.13.   Mxenes

2.2.14. Other Functional Separator

 

 

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

This is a nicely written manuscript from Ryohei Mori that presents and summarizes recent developments of functional separators in lithium sulfur batteries (LSBs) for solving electrode deterioration caused by the lithium polysulfide shuttle effect. I think this manuscript could be appealing enough of readers of “Electrochem” and be published by “Electrochem” with minor revisions.

 

1. In the part 2.1, the author described the inhabitation of Li dendrites by the introduce of other nanoparticle- or nanolayer-based metal materials. I am curious whether it would be better to functionalize the anode-facing separators or the Li anode with nanoparticles.

 

2. The separators the author summarized in Table II seem to be on the cathode side. However, the caption of Table II is “Table II. Comparative performances of LSB with various type of materials on separator anode side.” Moreover, the size of the Table I seems to be different from that of Table II.

 

3. As the author mentioned, some of the functional materials could prevent LiPS shuttle effect by capturing LiPS, some of the functional materials are also expected to possess catalytic activity and good mechanical strength for LSBs. Is building a separator with different functional domains a strategy to achieve multiple goals?

 

4. Is there any study that functionalizes both sides of the separator to get a better performance?

 

5. The author summarized the separators classified by materials in the part 2. I am wondering whether you need to add a subtitle to discuss the separators facing to anode and cathode separately, as it is a little bit confusing that the titles of both part 2.4 and 2.14 are “Other Functional Separator Materials”.

Comments on the Quality of English Language

Line 30 against electrochemistry variation and stable usage for application in various types of elec

Line 37 (LSBs) could be one of alternative candidate rechargeable batteries due to their high theo

Line 47 toxic element, LSBs can be considered as one of the candidates for next generation re

Line 68 As LiPS concentration increases as this electrochemical reaction proceeds, the viscos

Line 194 discharge, LiPS are spreads out from the sulfur cathode towards the lithium anode metal.

Line 229 PP–SiO₂ separator, electrolyte wettability and thermal stability waswere properly improved.

Line 278 sites for polysulfides and thus prevents their transportation between electrodes49, 50. The

Line 301 as Lewis alkali to form DME-LiF clusters.  ThisThese clusters are viscous sol and form dense

Line 1040 In general, electronic resistance and ion conductivity needs to be high for LSB sepa

Line 1043 Tortuosity is also an importanceimportant factor. Tortuosity is a quantity to describe the morphol

Line 1054 20 - 50 µm whereas that of commercial separator thickness areis 20 - 25 µm148.  Thinner

Line 1162 In summary, it is necessary to think thatabout whether an applied material on separator is

Author Response

Green Science Alliance Co. Ltd

2-22-11 Obana Kawanishi-city, Hyogo prefecture 666-0015 JAPAN

 

                                                                                                                             

 

                                                                     October 23 2023

 

Editor in Chief

Electrochem

 

Dear Editor in Chief and Reviewer 3

 

Please find the revised manuscript “Separator Materials for Lithium Sulfur Battery – A Review” which I respectfully resubmit for consideration for publication in “Electrochem”.  I am most grateful to the editor and reviewers whose comments have helped to produce an improved manuscript.

 

 

Sincerely yours,

 

Ryohei Mori

 

************************************

Dr. Ryohei Mori

Green Science Alliance Co. Ltd

(Fuji Pigment Co., Ltd. Group)

2-22-11 Obana Kawanishi-city,

Hyogo Pref. 666-0015 JAPAN

TEL : +81-72-759-8501

FAX : +81-72-759-9008

mail:moriryohei@fuji-pigment.co.jp

WEB : http://www.fuji-pigment.co.jp/

************************************

 

 

Reviewer : 3

 

Comments to the Author

 

1. In the part 2.1, the author described the inhabitation of Li dendrites by the introduce of other nanoparticle- or nanolayer-based metal materials. I am curious whether it would be better to functionalize the anode-facing separators or the Li anode with nanoparticles.

 

Thank you for referee’s comment and I have added following explanations and references in part 2.1.

 

Not only introducing metal material but also copper was functionalized to lithium metal anode to prepare 3D Cu/Li and copper mesh / Li composite anode. Yang et al. had clarified that Li dendrites growth was successfully suppressed with 3D Cu/Li structured anode which can operate for 600 h and demonstrated low voltage hystere-sis^41,42.

 

2. The separators the author summarized in Table II seem to be on the cathode side. However, the caption of Table II is “Table II. Comparative performances of LSB with various type of materials on separator anode side.” Moreover, the size of the Table I seems to be different from that of Table II.

 

Thank you very much to referee’s comment for exactly pointing out the mistake and I have corrected the Table II caption from “anode side” to “cathode side”. 

 

I have also made the Table I size to be smaller to be same size as that of Table II.

 

3. As the author mentioned, some of the functional materials could prevent LiPS shuttle effect by capturing LiPS, some of the functional materials are also expected to possess catalytic activity and good mechanical strength for LSBs. Is building a separator with different functional domains a strategy to achieve multiple goals?

 

Thank you very much to referee’s comment and I have added following explanation at the end of part 2.  In addition, I added Table III to emphasize the separator material with multifunction.

 

In addition, all of materials which was applied to LSB separators in this study were summarized in Table I and II, depending upon whether they are on anode or cathode side. The one of major role for those separator materials were to capture LiPS in order to suppress shuttle effect.  Furthermore, applied materials with both lithium polysulfide adsorption and catalytic activities, were presented in Table III as multifunctional materials.

 

Table III.

Comparative performances of LSB with various type of materials with both lithium polysulfide adsorption and catalytic activities.

 

4. Is there any study that functionalizes both sides of the separator to get a better performance?

 

Thank you for referee’s comment and I have added following explanations and references at the end of part 2.

 

It should be mentioned here that various type of materials were applied as LSB sepa-rator as described so far, and classified as whether they are on anode or cathode side of separator.  However, even we have been explained as they are applied on one side of separator, some of them are applied on both side of separator.  We explained in the way of emphasizing that applied material acted as functional material on particular side.  As one of the example we would like to introduce which clearly states MnO₂ functional layers on both anode and cathode sides. Tian et al. demonstrated that MnO₂ was able to suppress LiPS migration with its chemical adsorption ability, which resulted in improving LSB electrochemical performance¹⁵³.    

 

5. The author summarized the separators classified by materials in the part 2. I am wondering whether you need to add a subtitle to discuss the separators facing to anode and cathode separately, as it is a little bit confusing that the titles of both part 2.4 and 2.14 are “Other Functional Separator Materials”.

 

Thank you for referee’s comment and I added subtitle to clarify whether materials are facing anode side or cathode side.

 

2.1. Separator Material facing Anode Side

2.2. Separator Material facing Cathode Side

 

Comments on the Quality of English Language

 

Line 30 against electrochemistry variation and stable usage for application in various types of elec

 

Line 37 (LSBs) could be one of alternative candidate rechargeable batteries due to their high theo

 

Line 47 toxic element, LSBs can be considered as one of the candidates for next generation re

 

Line 68 As LiPS concentration increases as this electrochemical reaction proceeds, the viscos

 

Line 194 discharge, LiPS are spreads out from the sulfur cathode towards the lithium anode metal.

 

Line 229 PP–SiO2 separator, electrolyte wettability and thermal stability waswere properly improved.

 

Line 278 sites for polysulfides and thus prevents their transportation between electrodes49, 50. The

 

Line 301 as Lewis alkali to form DME-LiF clusters.  ThisThese clusters are viscous sol and form dense

 

Line 1040 In general, electronic resistance and ion conductivity needs to be high for LSB sepa

 

Line 1043 Tortuosity is also an importanceimportant factor. Tortuosity is a quantity to describe the morphol

 

Line 1054 20 - 50 µm whereas that of commercial separator thickness areis 20 - 25 µm148.  Thinner

 

Line 1162 In summary, it is necessary to think thatabout whether an applied material on separator is

 

Thank you so much for referee’s comment to exactly pointing out English grammatical error as above, and I have corrected all of those points as shown in red letter in the articles.

 

 

 

Thank you very much for referee’s comment to improve my manuscript and it should be noted here that in addition, I have added 7 references and tables (I, II, III) are modified accordingly.   

 

 

Author Response File: Author Response.pdf