High-Performance Ni-Co Sulfide Nanosheet-Nanotubes Grown on Ni Foam as a Binder Free Electrode for Supercapacitors
Round 1
Reviewer 1 Report
There are no major changes in this submission compared to the previous one. Therefore, my recommendation regarding the rejection of the manuscript is unchanged. Moreover, the writing is very poor.
The major concern about the originality, the presentation of the charge capacity were not solved. Therefore, this work should be rejected.
- The presence of well-defined redox peaks in the cyclic voltammograms suggests the battery-type response. The pseudocapacitive response should have rectangular or quasi rectangular CV shapes, like carbon materials. There are a lot of work , including the reference the authors provided, that miss-leads researcher in this field. The authors can find the proper answer in references: "To Be or Not To Be Pseudocapacitive?",D. Bélanger et al., J. Electrochem. Soc. 2015 volume 162, issue 5, A5185-A5189 and "A Guideline for Reporting Performance Metrics with Electrochemical Capacitors: From Electrode Materials to Full Devices", A. Balducci et al., J. Electrochem. Soc. 2017 volume 164, issue 7, A1487-A1488. Therefore, charge capacity must be presented as C or mAh, not F.
- I already gava the authors a chance to improve the manuscript to reach a certain level of originality for publication. The first version is just a duplication of what was already published in literature. But there is no change in the new version. There is no dependence of electrochemical properties on the morphology, only one morphology is reported. What is the dependence?One-step hydrothermal synthesis is not a new way (even relatively) to prepare Ni-Co sulfide, it was already widely reported in literature.
- The authors should read more papers to see what is the nanosheet, the marked ones in the manuscript areapparently not nanosheets.
Author Response
Please see the attachment
Author Response File: 
Author Response.docx
Reviewer 2 Report
The presented manuscript needs a revision and should be strongly revised. All the below comments should be applied. Overall the results section should be completely improved, more evidence, more discussions should be added.
It is very important.
The authors should provide a separate file and responded to all the below comments and then highlighted all changes in the manuscript.
1- Why Ni and Co were chosen?
2- The main parameter for XRD pattern should be added. lattice and sizes from XRD.
3-What is the benefit of hydrothermal method for synthesis of this composite?
4-How is the performance of single metal sulfide (Co and Ni)?
5-Electrochemical section needs more details and discussions.
6-Fig. 5a: the sample name cover the results and the place should change.
7-What is the reason for increasing to 500 cycles of Nickel cobalt oxide in cycle performance comparison (Fig. 6e)?
8-Fig 5c: why the position of peak potentials changed in the different scan rate?
9- more discussions for XPS results should be added.
Author Response
Please see the attachment
Author Response File: Author Response.doc
Reviewer 3 Report
The article “High-Performance Ni-Co sulfide nanosheet-nanotubes grown on Ni foam as a binder free electrode for supercapacitors” describes the fabrication, physical, and electrochemical characterization of Ni-Co sulfide electrodes for supercapacitors. The introduction is detailed and the methods are suitable to be able to reproduce the results. The physical characterization of the produced materials are well done and detailed showing clearly interesting aspects which are well discussed including the nanotubes growing form the nanosheets. However, some aspects of the electrochemical characterization are unclear and need further expansion, and more care should be taken in figure preparation
Specifically:
· Figure 3 e) there is no scale bar on this image
· Figure 2 – y axis is labelled ‘indensity’ rather than intensity or counts
· My major concern is in the shape of the cyclic voltammograms in Figure 5a and 5c. The x-axis of these reads right to left which goes against convention. However the shape of the cyclic voltammograms indicates that the sample is showing reduction peaks at higher potentials (0.4V vs Hg/HgO) than oxidation peaks (0.25V vs Hg/HgO). This would suggest a problem with the experimental set-up itself, with the sample experiencing from 0 to -0.6V vs Hg/HgO rather than 0 to +0.6V vs Hg/HgO. The data has clearly been presented with an inverted axis suggesting the authors were aware of the strange shape of the CVs should they be plotted the conventional way.
· The authors should comment of why the galvanostatic charge/discharge tests only went from 0 to 0.5V vs Hg/HgO, a different range to the CVs
· The electrolyte used (6M KOH) should be added to the caption.
Author Response
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Author Response File: Author Response.doc
Round 2
Reviewer 1 Report
None of the reviewer's comments were addressed in this revision. The authors even completely ignored one of the comments without mentioning it in the response. It wastes of time for doing peer review if the authors don't follow the comments and the manuscript is continuously passed to another round of the revision.
Author Response
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Author Response File: Author Response.doc
Reviewer 2 Report
The revised manuscript has been improved and the authors applied my comments.
Author Response
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Author Response File: Author Response.doc
Reviewer 3 Report
The authors have done a good job overall of addressing the reviewers comments.
However, my concern remains around Figure 5a) and Figure R1a1 in the response letter. Fundamentally there is an oxidation peak in both of these systems at a lower potential than it's redox couple. Can the reviewers describe the faradic process going on at +0.25V of the positive sweep (oxidation) and at +0.425V of the reverse sweep (reduction)?. The CV shape shown in Figure 3c is perfectly conventional as is Figure R1a2, why is such a shape not observed in Figure 5a?
Author Response
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Author Response File: Author Response.doc
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
High-performance Ni-Co sulfide nanosheet-nanotubes grown on Ni foam as a binder free electrode for supercapacitors
The presented manuscript needs a revision and should be strongly revised. All the below comments should be applied. Overall the results section should be completely improved, more evidence, more discussions should be added.
1- The abstract should be revised and more details valuable obtained data should be added.
2- Some grammatical errors and typo errors exist in the manuscript.
3- Why Ni and Co were chosen?
4- Page 2, line 78: one of the “NH4F” should be deleted.
5- Figure 2 should be revised. The complete intensity of peaks should be shown. The name of two samples should be written on the XRD patterns.
6- Page 4, line 126? Cation exchange?
7- The main parameter for XRD pattern should be added. lattice and sizes from XRD.
8- A comparative table should be added to compare the results of this work with previous published works.
9- The introduction section should be improved.
10-XPS results for this material should be added.
11-Fig. 3: could EDS mapping add to this figure?
12-What is the benefit of hydrothermal method for synthesis of this composite?
13-How is the performance of single metal sulfide (Co and Ni)?
14-Electrochemical section needs more details and discussions.
15-Fig. 5c,a,d: space between number and units in the figure should be applied.
16-What is the reason for increasing to 500 cycles of Nickel cobalt oxide in cycle performance comparison (Fig. 6e)?
17-Fig 5c: why the position of peak potentials changed in the different scan rate?
18-More details for the experimental section of electrochemical tests should be added.
Author Response
Detailed response was shown in word file.
Reviewer 2 Report
This work presents the preparation of Ni-Co sulfide nanotubes arrays on Ni foam by the hydrothermal method as supercapacitor electrodes. The manuscript can be reconsidered for publication after addressing following comments.
- The oxide and sulfide electrodes show cyclic voltammograms with the presence of redox peaks, revealing these electrodes are battery-type materials. Therefore, the charge storage capacity should be presented as C or mAh, not capacitance (F). Moreover, discussion about pseudocapacitors and capacitance in the manuscript should be revised. Please correct it in the entire manuscript.
- Please state what is the difference of this work with many similar works reported in the literature about the hydrothermal synthesis of Ni-Co sulfides for supercapacitors.
- SEM and TEM images revealed the formation of nanotubes, I could not see any nanosheets from the results.
- Discussion about the high capacity of the metal oxide electrodes should be revised. Their high capacity is mainly due to the redox reactions at the electrodes, that can be occurred either at the surface or in the bulk. The authors should update recent literature (such as: Applied Surface Science 422, 2017, 492-497; Advanced Science 2019, 1801797).
- All the current values in Figure 5 should be normalized.
- Please revise over-interpretation phrases in the manuscript:
Abstract: “In this work a new scientific strategyhas been provided for the sulfide-induced with noticeable electrochemical performance of nickelcobaltite compounds and supply a hopefully route for next generation high-performancesupercapacitor electrodes.”
Introduction: ”Our work not only proposes a simple route for improving the capacitance ofNi-Co compounds but provides a guideline for developing performance-enhanced supercapacitors.”
Conclusions: “Our findings provide a scientific strategy forthe sulfide-induced remarkable electrochemical performance of nickel cobaltite compounds andsupply a hopefully route for next generation high-performance supercapacitor electrodes.”
- Please compare the electrode performance in this work with those reported in the literature.
- What is the charge storage mechanism of the prepared electrode?
- Finally, the writing should be carefully polished.
p { margin-bottom: 0.1in; line-height: 115%; }Author Response
Detailed respond was shown in word file.
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
The authors should provide a separate file to response to all my comments and respond to each comment and clarify the changes in the manuscript. I cannot see these responses in the manuscript file or any separate file.
Reviewer 2 Report
Many of the comments are responded very poor. The major concern about the originality, the presentation of the charge capacity were not solved. Therefore, this work should be rejected.
- The presence of well-defined redox peaks in the cyclic voltammograms suggests the battery-type response. The pseudocapacitive response should have rectangular or quasi rectangular CV shapes, like carbon materials. There are a lot of work , including the reference the authors provided, that miss-leads researcher in this field. The authors can find the proper answer in references: "To Be or Not To Be Pseudocapacitive?",D. Bélanger et al., J. Electrochem. Soc. 2015 volume 162, issue 5, A5185-A5189 and "A Guideline for Reporting Performance Metrics with Electrochemical Capacitors: From Electrode Materials to Full Devices", A. Balducci et al., J. Electrochem. Soc. 2017 volume 164, issue 7, A1487-A1488.
- I already gava the authors a chance to improve the manuscript to reach a certain level of originality for publication. The first version is just a duplication of what was already published in literature. But there is no chance in the new version. There is no dependence of electrochemical properties on the morphology, only one morphology is reported. What is the dependence?One-step hydrothermal synthesis is not a new way (even relatively) to prepare Ni-Co sulfide, it was already widely reported in literature.
- The authors should read more papers to see what is the nanosheet, the marked ones in the manuscript are apparently not nanosheets.
- The over-interpretation phrases are still in the revised manuscript, nothing changes. These are the ones:
Abstract: “supply a hopefully route for next generation high-performance supercapacitor electrodes.”
Introduction:”provides a guideline for developing performance-enhanced supercapacitors.”
Conclusions: “hopefully route for next generation high-performance supercapacitor electrodes.”
No hopefully route and guideline are reported in this work. It just repeated somethings already reported in literature.
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