Enhanced Electrochemical Performance of LaMnO3 Nanoparticles by Ca/Sr Doping
, Xu Guo 1, Xiaoyun Jin 1, Lei Wang 1,*, Songtao Dong 1,* and Jian Chen 3
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsI cannot see any novelty in this work
very similar works were done years ago
Most references are quite old
Comments on the Quality of English LanguageAcceptable
Author Response
Reviewer #1:
Most references are quite old
Reply: Thanks for your comments. We have added the recent relevant literature in revised manuscript.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for AuthorsDear authors,
Below are a few of my comments:
1. The SEM images in Figure 2 are really with a bad contrast; if possible try replacing them with better contrast micrographs.
2. I'll suggest improving on the introduction section fo your paper; you discuss oxygen defects in oxides and layered oxides in the paragraph starting in line 40 and thereafter. It would be pertinent if you could discuss the methods of studying oxygen defects and transport such as neutron diffraction; please have a look at this paper for reading and citing your work here, https://doi.org/10.1039/D3RA01772A.
3. Could you please provide the details of the Kramers–Kronig residual analysis for the EIS data (figure 6d) validation or add them as SI to the manuscript?
4. Perovskites such as LSM have been studied extensively for solid oxide cells and one major problem with them has been the Sr segregation (please read and cite this, https://doi.org/10.1557/s43579-023-00371-0) which reduces performance over time. Have the authors considered that issue? More importantly, I suggest including this in the introduction section at least, to make sure readers get a clear picture.
Thanks.
Author Response
Reviewer #2:
- The SEM images in Figure 2 are really with a bad contrast; if possible try replacing them with better contrast micrographs.
Reply: Thanks for your comments. We have replaced the SEM images in Figure 2 with better contrast micrographs.
- I'll suggest improving on the introduction section fo your paper; you discuss oxygen defects in oxides and layered oxides in the paragraph starting in line 40 and thereafter. It would be pertinent if you could discuss the methods of studying oxygen defects and transport such as neutron diffraction; please have a look at this paper for reading and citing your work here, https://doi.org/10.1039/D3RA01772A.
Reply: Thank you for your nice suggestion. We have added the methods of studying oxygen defects and citted the above paper in our work.
- Could you please provide the details of the Kramers–Kronig residual analysis for the EIS data (figure 6d) validation or add them as SI to the manuscript?
Reply: Thanks for your comments. We have added the details of the analysis for the EIS data, which was analyzed by the Zview software. The process is as follows: The impedance spectrum was fitted to an equivalent circuit (shown in the inset), comprising the internal resistance (Rs), charge transfer resistance Rct, Warburg Element (open) Wo, and Constant Phase Element CPE. The Rs of LMO, LCM, and LSM electrodes are 1.45, 1.54, and 1.01 Ω, respectively, and the corresponding Rct are 0.48 Ω, 0.36 Ω, and 0.38 Ω, respectively. Notably, the lowest Rct of LCM sample exhibits its good electrochemical performance.
- Perovskites such as LSM have been studied extensively for solid oxide cells and one major problem with them has been the Sr segregation (please read and citethis, https://doi.org/10.1557/s43579-023-00371-0) which reduces performance over time. Have the authors considered that issue? More importantly, I suggest including this in the introduction section at least, to make sure readers get a clear picture.
Reply: Thank you for your nice suggestion. Supercapacitors are not used in high temperature environments, so we are not concerned about the problem of Sr separation. We have added this in the introduction section.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for AuthorsManuscript reports on synthesis and characterization of Ca or Sr-dopped LaMnO3 powders. These materials were rather intensively studied two decades. In present paper authors are focused on electrochemical properties of compounds and this brings some novelty. In general, the manuscript is well written and organized. Nevertheless, there are several points to correct:
1) line 43, correct space group is ‘Pm-3m’
2) line 113, ‘three-electrode setup with a Hg/HgO (SCE) reference electrode ’ SCE is Hg/Hg2Cl2 electrode, while Hg/HgO is a different type electrode
3) Figure 1 is absent in manuscript. I suppose it was lost during the conversion to PDF.
4) Figure 2, electron diffraction patterns were distorted – please check the horizontal/vertical proportions
5) Authors determine the oxygen deficiency (delta) by means of XPS analysis which gives only information on surface of sample and with low accuracy. The red-ox titration (e.g. iodometric titration) is well-known method for determination of oxygen content in manganites. This analysis would be very useful for accurate measurements.
Author Response
Reviewer #3:
- line 43, correct space group is ‘Pm-3m’
Reply: According to your suggestion, we have revised the correct space group of ‘Pm-3m’.
- line 113, ‘three-electrode setup with a Hg/HgO (SCE) reference electrode ’ SCE is Hg/Hg2Cl2 electrode, while Hg/HgO is a different type electrode
Reply: Thanks for your comments. We have deleted the ‘(SCE)’ in line 113.
- Figure 1 is absent in manuscript. I suppose it was lost during the conversion to PDF.
Reply: Thanks for your comments. You are right, it was lost when converting to PDF.
- Figure 2, electron diffraction patterns were distorted – please check the horizontal/vertical proportions
Reply: Thanks for your comments. We have checked the horizontal/vertical proportions and adjusted the horizontal/vertical proportions in Figure 2.
- Authors determine the oxygen deficiency (delta) by means of XPS analysis which gives only information on surface of sample and with low accuracy. The red-ox titration (e.g. iodometric titration) is well-known method for determination of oxygen content in manganites. This analysis would be very useful for accurate measurements.
Reply: Thanks for your comments. The red-ox titration (e.g. iodometric titration)referred to by the reviewer is the accurate measurement of the oxygen content in manganese oxide. In our work, we use XPS to distinguish the amount of different types of oxygen to explain the changes in the electrochemical properties of perovskites. XPS method has been adopted to analyze the number of oxygen vacancies in existing literature[Yan, D., Wang, W., Luo, X., Chen, C., Zeng, Y., & Zhu, Z, NiCo2O4 with oxygen vacancies as better performance electrode material for supercapacitor, Chem. Eng. J. 2018, 334: 864-872].
Author Response File: Author Response.pdf
Reviewer 4 Report
Comments and Suggestions for AuthorsLine no 13, remove the word We in the line. The author should highlight the proposed target application and novelty in the manuscript.
Some references used in the studies are almost very old. The authors must mention the recent relevant literatures.
Line no 74, avoid the word we in the manuscript. on what basis the authors selected the agitation of 24 hrs in the study and the temperature selection is not accurate from reviewer point of view.
Step size of the XRD analysis is not mentioned and the 6°/min is high? Why did the authors selected like that?
The initial mass of the powder used for TGA studies is not mentioned any where. Line no 124 and 125 a little contractory is there. Why there is 50 deg increase in temperature occured in the study?
How did the authors intrept the lattice distortion in the structure ? Fig 1 is not mentioned in the manuscript.
The XRD peak analysis is also not available in the manuscript. In SEM image there is no machine information available. Why did the author crop those details in the manuscript. It is too difficult to conclude the particle size from SEM analysis.
The image looks like a clumsy one and is not able to see any feature. in SADP analysis is not mentioned in manuscript.
It is mentioned that LCM having the good surface area as compared to counterparts. However, the details were not discussed with existing literatures and correlation is missing.
The XPS plots should be discussed in details with the amount of binding energy present in the material. It cropped the graph down and it is too difficult to maximize and see the features present on it,
The caption of the figure and tables should be rewrite.
Comments on the Quality of English Language
Avoid the word We and minor changes need to polish the language
Author Response
Reviewer #4:
- Line no 13, remove the word We in the line. The author should highlight the proposed target application and novelty in the manuscript.
Reply: Thank you for your nice suggestion. We have removed the word ‘We’ in the line no 13.
- Some references used in the studies are almost very old. The authors must mention the recent relevant literatures.
Reply: According to your suggestion, we have added the recent relevant literature in new revised manuscript.
- Line no 74, avoid the word we in the manuscript. on what basis the authors selected the agitation of 24 hrs in the study and the temperature selection is not accurate from reviewer point of view.
Reply: Thank you for your nice suggestion. We have removed the word ‘We’ in the line no 74. The selected the agitation of 24 hrs in the study,this is what we have concluded after many experiments. The temperature selection ( 80 ℃) is the temperature used in reference [Ma, P. P., Lu, Q. L., Lei, N., Liu, Y. K., Yu, B., Dai, J. M., Li, S.H. & Jiang, G. H, Effect of A-site substitution by Ca or Sr on the structure and electrochemical performance of LaMnO3 perovskite, Electrochim. Acta 2020, 332: 135489].
4.Step size of the XRD analysis is not mentioned and the 6°/min is high? Why did the authors selected like that?
Reply: Thanks for your comments. The step size of the XRD analysis is 0.02. We have checked the scanning speed of 6 °/min. The scanning speed is calculated based on the scanning range and time used in the XRD test.
5.The initial mass of the powder used for TGA studies is not mentioned any where. Line no 124 and 125 a little contractory is there. Why there is 50 deg increase in temperature occured in the study?
Reply: Thanks for your comments. We have added the initial mass of the powder used for TGA studies. We have made corresponding modifications in this part, as follows: A significant reduction in the mass of the precursor material was observed within the temperature range of 300 to 600°C. Beyond 600°C, the weight remained relatively stable. Consequently, a calcination temperature of 650°C was determined as appropriate for the LMO precursors. Subsequent XRD analysis indicated the absence of synthesized LMO, prompting an increase in the calcination temperature to 700°C. This adjustment resulted in subsequent XRD patterns that confirmed the successful production of LMO. According to the results of thermal analysis, the calcination temperature is selected. The products of different calcination temperatures were analyzed by XRD to determine the calcination temperature in this study. In order to quickly determine the temperature, we use an increase of 50 degrees.
- How did the authors intrept the lattice distortion in the structure ? Fig 1 is not mentioned in the manuscript.
Reply: Thanks for your comments. The lattice distortion in the structure is determined by the shift of diffraction peaks in the XRD results, which is similar to the results reported in reference[Ma, P. P., Lu, Q. L., Lei, N., Liu, Y. K., Yu, B., Dai, J. M., Li, S.H. & Jiang, G. H, Effect of A-site substitution by Ca or Sr on the structure and electrochemical performance of LaMnO3 perovskite, Electrochim. Acta 2020, 332: 135489]. Figure 1 was lost when converting to PDF.
- The XRD peak analysis is also not available in the manuscript. In SEM image there is no machine information available. Why did the author crop those details in the manuscript. It is too difficult to conclude the particle size from SEM analysis.
Reply: Thanks for your comments. We have added the XRD peak analysis in the manuscript, as follows:In comparison to the standard card (PDF 50–0297), the presence of peaks at 23.0°, 32.6°, 40.1°, 46.7°, 52.7°, and 58.2°, corresponding to the (110), (200), (022), (220), (130), and (024) crystal planes, respectively, indicates the successful synthesis of single-phase LMO and LSM samples. Similarly, when compared to the standard card (PDF 50–0299), the absence of any additional peaks in the diffraction pattern confirms the synthesis of single-phase LCM samples. It’s our mistake, the particle size should be concluded from TEM analysis. We have made the corresponding description in the revised manuscript.
- The image looks like a clumsy one and is not able to see any feature. in SADP analysis is not mentioned in manuscript.
Reply: Thanks for your comments. We have replaced the SEM images in Figure 2 with better contrast micrographs. The SAED results in our work was used to indicate the presence of a polycrystalline structure in all three samples. We have mentioned in manuscript.
- It is mentioned that LCM having the good surface area as compared to counterparts. However, the details were not discussed with existing literatures and correlation is missing.
Reply: Thanks for your comments. We have added the specific surface area of the LMO, LCM, and LSM samples. LCM has the good surface area as compared to LMO and LSM samples. This is also to explain why the electrochemical performance of LCM is the best among the three samples, not compared with the specific surface area reported in other literature.
- The XPS plots should be discussed in details with the amount of binding energy present in the material. It cropped the graph down and it is too difficult to maximize and see the features present on it,
Reply: Thanks for your comments. X-ray photoelectron spectroscopy (XPS) is employed for the identification of elements present in the sample as well as the determination of their respective valence states. The elemental composition of each sample is determined by analyzing the complete spectrum diagram, followed by a high-resolution examination of each element to ascertain its valence state. Specifically, the high-resolution spectra of the oxygen element were subjected to fitting analysis in order to quantify the content of three distinct oxygen species. This information was subsequently utilized to elucidate the variations observed in the electrochemical properties among the three samples.
- The caption of the figure and tables should be rewrite.
Reply: According to your suggestion, we have rewrited the caption of the figure and tables.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
Comments and Suggestions for AuthorsReferences added to the revised version are by the same authors (self citation). So, my main point made for the previeous submission is not properly answered, that is similar works has been carried out years ago. Therefore, I cannot see any novelty in this work
Author Response
Reviewer #1:
- References added to the revised version are by the same authors (self citation).
Reply: Thanks for your comments. We have added the more recent references in revised manuscript.
- So, my main point made for the previeous submission is not properly answered, that is similar works has been carried out years ago. Therefore, I cannot see any novelty in this work
Reply: Thanks for your comments. One of the primary objectives of this study is to enhance the electrochemical performance of LaMnO3 through modifications in the preparation process. Specifically, the impact of doping elements with varying ionic radii on the microstructure, specific surface area, oxygen vacancy concentration, and electrochemical performance was investigated. Notably, this research distinguishes itself from previous reports by including an analysis of the specific surface area post-doping, thereby providing additional evidence for the enhancement of electrochemical performance. Furthermore, it should be noted that the depiction of electrochemical properties differs from the conventional units employed in the majority of scholarly publications.
In short, we wish above elucidations make our draft more solid and transparent. And we wish our new effort do address your comments on this draft.
Thank you again!
Yours sincerely,
Dr. Lei Wang and Song-Tao Dong
Reviewer 2 Report
Comments and Suggestions for AuthorsAccept
Author Response
Thanks to the reviewers for their review and recognition of this study
Reviewer 3 Report
Comments and Suggestions for AuthorsIn the revised manuscript authors have addressed most of reviewers' comments. Manuscript can be accepted.
Author Response
Thanks to the reviewers for their review and recognition of this study
Reviewer 4 Report
Comments and Suggestions for AuthorsThe authors have include majority of changes in the manuscript. however, I request the authors to refer the numbering of eqn as per journal standard and include in the manuscript.
Comments on the Quality of English LanguageThe language is fine
Author Response
1.The authors have include majority of changes in the manuscript. however, I request the authors to refer the numbering of eqn as per journal standard and include in the manuscript.
Reply: Thanks for your comments. We have refered the numbering of eqn as per journal standard and include in the manuscript.
In short, we wish above elucidations make our draft more solid and transparent. And we wish our new effort do address your comments on this draft.
Thank you again!
Yours sincerely,
Dr. Lei Wang and Song-Tao Dong
