Review Reports - A Review of Recent Advances in Multivalent Ion Batteries for Next Generation Energy Storage

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

However, several sections would benefit from greater critical analysis, improved figure caption clarity, and clearer illustration of the cited literature. Some claims lack quantitative comparison or explanation. Refining these areas would enhance scientific rigor and reader impact.

Table 1 provides a comparison of the properties of different multivalent cations. However, the numbers in the table need to be double checked and improvements need to be made.
- The ionic radius of the ions in Table 1 is incorrect and needs to be revised. In the section talking about the obstacle in cathode compatibility (line 95~97), the authors state that “larger ionic radius and higher valence state of multivalent ions require host materials with open crystal frameworks and redox chemistries”. However, in the table, the ionic radius of Mg, Zn and Al are even smaller than Li, which is incorrect.
- The theoretical volumetric capacity is calculated based on the metal anode instead of the whole battery, which needs to be specified, because the values would be very different when taking the cathode and electrolyte into consideration.
- The paper also discussed Ca batteries. The properties of Ca2+ also need to be added and compared here.
- For battery performance, comparative metrics, such as the voltage window, cycle life, are important and need to be added with corresponding references in a summary table for quick reference.

Several figures used in this review paper illustrate important concepts but appear adapted from prior works without clear originality or detailed captions. The captions need to be checked for each figure carefully and reference papers need to be added to the captions.
- Figure 1: Replace “multi-ion transfer” with “multivalent ion transfer” for clarity.
- Figure 2: reference needs to be added.
- Figure 3: reference needs to be added. The rate capability is highlighted in the text and caption, whereas the figure does not indicate the C rate of the different resulting capacities.
- Figure 5: The caption is incorrect and does not correspond to the content in the figures. For example, figure (a) is a schematic picture, while the caption says EIS for coated Zn.

In section 3, “advances in core chemistries”, some references are cited but correspond to unrelated works. The cross-consistency need to be verified between citations and context. The original papers need to be cited for the previous work instead of the review papers.
- In section 3.1 Magnesium-Ion Batteries, the only reference cited is a review paper (reference 19). However, reference 19 is a review on Zn ion batteries, which is not related to the content discussed. No reference can be found in this paper that corresponds to the contents discussed. Also, reference need to be added to the content from line 134 to 136.
- In section 3.2 Zinc-Ion Batteries, the only reference cited is also a review paper (reference 20). From line 165 to 167, the authors state that the surface engineering strategy was developed by Li et al. However, the work is just discussed and summarized in the review paper by Li et al., not conducted by them. The original work needs to be cited in addition to the review paper and the content needs to be revised to reference to the correct authors.
- In section 3.2 Zinc-Ion Batteries, in line 169, the abbreviation Zn-NTA is not explained. What is the Zn-NTA coating? Clearer explanation and corresponding reference need to be added.
- In section 3.4 Calcium-Ion Batteries, in line 242, the abbreviation CALS is not explained. What is the CALS electrolyte need to be further explained.

In section 4, “cross-cutting strategies”, from line 279 to 283, the reference paper is missing for this work.

In section 5, “intelligent optimization and smart systems”, the authors discussed in situ and operando characterization techniques for mechanism studies, which is irrelevant to the topic here. A new section is needed for the discussion of these contents, or the title of this section needs to be revised to fit the broader topics.
For section 6, “applications and roadmap”, the roadmap (Figure 7) is a good concept but lacks supporting rationale and appears speculative. Quantitative reasoning or references for the proposed timeframes need to be provided (e.g. pilot projects). Scaling barriers (manufacturing, electrolyte cost, safety) that could delay adoption need to be discussed. A critical evaluation of the commercial readiness of each chemistry needs to be provided, especially for Al, Mg and Ca batteries, not just their potential.

Comments for author File: Comments.pdf

Author Response

Thank you for taking the time to provide us a very thorough and thoughtful review. We concurred with all of your suggestions. Below are how we addressed each of your comments. Your text is in red, and our response is in black.

The manuscript presents a well-structured review of recent advances in multivalent ion batteries, covering Mg, Zn, Al, and Ca batteries. It provides a balanced overview of electrolyte design, interfacial engineering, sustainability considerations, and intelligent optimization strategies. The discussion connects fundamental chemistry with application-oriented perspectives. However, several sections would benefit from greater critical analysis, improved figure caption clarity, and clearer illustration of the cited literature. Some claims lack quantitative comparison or explanation. Refining these areas would enhance scientific rigor and reader impact.

We went through the paper and attempted to increase the quantitative analysis/comparisons. We also augmented the degree of critical analysis. We added 20 additional references to further help provide a more substantive outline of the work being done in this field.

1. Table 1 provides a comparison of the properties of different multivalent cations. However, the numbers in the table need to be double checked and improvements need to be made.

- The ionic radius of the ions in Table 1 is incorrect and needs to be revised. In the section talking about the obstacle in cathode compatibility (line 95~97), the authors state that “larger ionic radius and higher valence state of multivalent ions require host materials with open crystal frameworks and redox chemistries”. However, in the table, the ionic radius of Mg, Zn and Al are even smaller than Li, which is incorrect.
- The theoretical volumetric capacity is calculated based on the metal anode instead of the whole battery, which needs to be specified, because the values would be very different when taking the cathode and electrolyte into consideration.
- The paper also discussed Ca batteries. The properties of Ca2+ also need to be added and compared here.
- For battery performance, comparative metrics, such as the voltage window, cycle life, are important and need to be added with corresponding references in a summary table for quick reference.

Table 1 was updated to reflect these recommendations. We found it was rather difficult to read, so we broke some of the material into a new table (Table 2).

2. Several figures used in this review paper illustrate important concepts but appear adapted from prior works without clear originality or detailed captions. The captions need to be checked for each figure carefully and reference papers need to be added to the captions.

- Figure 1: Replace “multi-ion transfer” with “multivalent ion transfer” for clarity.
- Figure 2: reference needs to be added.
- Figure 3: reference needs to be added. The rate capability is highlighted in the text and caption, whereas the figure does not indicate the C rate of the different resulting capacities.
- Figure 5: The caption is incorrect and does not correspond to the content in the figures. For example, figure (a) is a schematic picture, while the caption says EIS for coated Zn.

We updated Figures 1 and 5 accordingly. We generated Figure 2 so no reference was necessary. We removed Figure 3 because we felt that it provided little new value to the paper.

3. In section 3, “advances in core chemistries”, some references are cited but correspond to unrelated works. The cross-consistency need to be verified between citations and context. The original papers need to be cited for the previous work instead of the review papers.

- In section 3.1 Magnesium-Ion Batteries, the only reference cited is a review paper (reference 19). However, reference 19 is a review on Zn ion batteries, which is not related to the content discussed. No reference can be found in this paper that corresponds to the contents discussed. Also, reference need to be added to the content from line 134 to 136.
- In section 3.2 Zinc-Ion Batteries, the only reference cited is also a review paper (reference 20). From line 165 to 167, the authors state that the surface engineering strategy was developed by Li et al. However, the work is just discussed and summarized in the review paper by Li et al., not conducted by them. The original work needs to be cited in addition to the review paper and the content needs to be revised to reference to the correct authors.
- In section 3.2 Zinc-Ion Batteries, in line 169, the abbreviation Zn-NTA is not explained. What is the Zn-NTA coating? Clearer explanation and corresponding reference need to be added.
- In section 3.4 Calcium-Ion Batteries, in line 242, the abbreviation CALS is not explained. What is the CALS electrolyte need to be further explained.

We went through the paper and fixed all the referencing issues. When we submitted the initial paper there was some misalignment between the references and our reference list. That has been corrected. We also pulled information from primary sources (as opposed to review articles). We also added a number of new references to better capture the breadth of research going on in the field.

4. In section 4, “cross-cutting strategies”, from line 279 to 283, the reference paper is missing for this work.

Corrected.

5. In section 5, “intelligent optimization and smart systems”, the authors discussed in situ and operando characterization techniques for mechanism studies, which is irrelevant to the topic here. A new section is needed for the discussion of these contents, or the title of this section needs to be revised to fit the broader topics.

Great suggestion. We corrected that portion of Section 5.

6. For section 6, “applications and roadmap”, the roadmap (Figure 7) is a good concept but lacks supporting rationale and appears speculative. Quantitative reasoning or references for the proposed timeframes need to be provided (e.g. pilot projects). Scaling barriers (manufacturing, electrolyte cost, safety) that could delay adoption need to be discussed. A critical evaluation of the commercial readiness of each chemistry needs to be provided, especially for Al, Mg and Ca batteries, not just their potential.

We added more discussion to better explain/justify the roadmap. We also added a table that supports the projected roadmap.

Reviewer 2 Report

Comments and Suggestions for Authors

This review has summarized recent advances across key chemistries of multivalent metals or non-alkali metal-ion batteries (magnesium, zinc, aluminum, and calcium). The authors highlighted innovations in solvation shell engineering, electrolyte additive strategies, cathode design and interfacial stabilization. The review is suggested to be published. Here is some suggestions to further improve the quality and comprehensiveness of this review:

I believe there should be more strategies for non-alkali metal-ion batteries that have been reported recently. For example, protein-based biomimicking strategies, SEI modification or electrolyte design. These advanced strategies are suggested to be introduced in the introduction section to enrich the content. Current version of introduction is not comprehensive.
In Figure 1, I think the "Multi-Ion Transfer" should be "Multivalent-ion Transfer". The right figure is a little misleading. There should be only one type of multivalent ions in the systems. Using M^x+ (x>1) should be better.
Table caption, "multivalent cations" should be "multivalent/monovalent cations".
In Figure 3 caption, the period "." should be added in the end.
The resolution of Figure 5 should be improved to meet the quality requirements of publication.
The logic of Section 7 is suggested to be further improved.

Author Response

Thank you for reviewing our paper and providing the insightful feedback. We concurred with all of your recommendations, and our updated paper is much stronger. Please see below for details on how we addressed each of your suggestions (your review is in red, our responses are in black):

I believe there should be more strategies for non-alkali metal-ion batteries that have been reported recently. For example, protein-based biomimicking strategies, SEI modification or electrolyte design. These advanced strategies are suggested to be introduced in the introduction section to enrich the content. Current version of introduction is not comprehensive.

We updated the introduction to include a paragraph that this discusses these advances.

In Figure 1, I think the "Multi-Ion Transfer" should be "Multivalent-ion Transfer". The right figure is a little misleading. There should be only one type of multivalent ions in the systems. Using Mx+ (x>1) should be better.

Corrected. The new figure is much clearer and contains more relevant information.

Table caption, "multivalent cations" should be "multivalent/monovalent cations".

Corrected

In Figure 3 caption, the period "." should be added in the end.

Corrected

The resolution of Figure 5 should be improved to meet the quality requirements of publication.

Corrected

The logic of Section 7 is suggested to be further improved.

We added more discussion to improve Section 7 and make it have a more logical flow.

Reviewer 3 Report

Comments and Suggestions for Authors

The manuscript presents a comprehensive and well-structured review of recent advances in multivalent ion batteries (MVIBs), covering magnesium-, zinc-, aluminum-, and calcium-based systems. I suggested that the manuscript should be accepted after minor revisions, with the following points addressed:

Figure 1 is overly simplified. It only shows the difference in charge density between monovalent and multivalent systems. To better reflect the technical challenges discussed in the text, it would be helpful if the figure could also illustrate key bottlenecks such as slow solid-state diffusion, strong ion–solvent interactions, and limited reversibility.
Table 1 lists "corrosion" as the main challenge for Al anode, it is not clear whether this refers to corrosion of the current collector or passivation/corrosion of the Al anode itself. This should be clarified. Moreover, Mg and Al also suffer from passivation.
Table 1 is not cited in the text.
On page 11, please clarify that zinc-flow batteries are used for grid storage because the workring principles differ significantly.

Overall, I find the manuscript suitable for publication once these minor issues are addressed.

Author Response

Thank you for the insightful and helpful review. We concur with all of your recommendations. Below are our point-by-point responses clarifying how we addressed your suggestions in our paper. Your review is in red, and our responses are in black.

Figure 1 is overly simplified. It only shows the difference in charge density between monovalent and multivalent systems. To better reflect the technical challenges discussed in the text, it would be helpful if the figure could also illustrate key bottlenecks such as slow solid-state diffusion, strong ion–solvent interactions, and limited reversibility.
We updated Figure 1 so that it is not as simple. While still conceptual, the updated figure provides more insights into how multivalent batteries differ from monovalent batteries.
Table 1 lists "corrosion" as the main challenge for Al anode, it is not clear whether this refers to corrosion of the current collector or passivation/corrosion of the Al anode itself. This should be clarified. Moreover, Mg and Al also suffer from passivation.
We clarified/fixed Table 1.
Table 1 is not cited in the text.
We corrected the text to include Table 1
On page 11, please clarify that zinc-flow batteries are used for grid storage because the workring principles differ significantly.
Updated! Thank you for pointing out that we needed to make that clarification.

Overall, I find the manuscript suitable for publication once these minor issues are addressed.

Reviewer 4 Report

Comments and Suggestions for Authors

The title “A Review of Recent Advances in Multivalent Ion Batteries for Next Generation Energy Storage” suggests a broad and comprehensive coverage of recent developments across multivalent ion battery systems. However, the current manuscript primarily provides an overview of several chemistries (Mg-, Zn-, Al-, and Ca-based systems) at a relatively general level, without in-depth analysis of specific components such as cathode materials, anode behaviors, electrolytes, or interfacial phenomena. As a result, the focus of the review remains somewhat diffuse, and it is unclear which technical aspect the authors intend to emphasize.

At its current level of generality, the manuscript lacks the depth and critical insight expected from a review article and may not meet the journal’s publication standards. A more specific and focused narrative would greatly strengthen the clarity, academic value, and contribution of this work.

For instance, the authors could have concentrated on a particular aspect such as the technical challenges associated with metallic anodes, the degradation mechanisms of cathode materials, or electrolyte engineering. Instead, the manuscript discusses each battery chemistry only in general terms, without detailed exploration of key issues. This lack of focus leads to inconsistencies, for example, dendrite formation is discussed for Zn-ion batteries but not for Mg-ion systems, even though both are known to experience such issues under certain conditions.

Moreover, while Section 4 (“Cross-cutting Strategies”) mentions several general approaches to overcome technical barriers, it does not provide sufficient linkage to specific battery systems or cite representative studies. Consequently, the discussion remains superficial and fails to deliver meaningful technical insight.

Additionally, Figure 7 (roadmap) lacks clear justification. The proposed development sequence (Zn → Al → Mg) is not supported by evidence or comparative analysis, and it may be difficult for readers to accept this progression without a rational basis or references.

While more detailed, section-by-section comments could be provided, the primary concerns lie in the overall direction, insufficient depth of analysis, and lack of specificity. For these reasons, I have chosen to focus on the general issues rather than detailed minor points.

Author Response

Thank you for the very thoughtful review. We concur that there was a lot that we could improve on with the paper. We made substantial changes to it to address your concerns. We hope that the updated paper is stronger. Please see below for our point-by-point responses. Your comments are in red and our responses are in black.

We added a paragraph into our introduction to better clarify our area of emphasis, with a focus on cross-cutting strategies. We also went through and provided significantly more references to help capture the breadth of research going on.

For a review paper to be impactful and suitable for publication in Electrochem, it would be beneficial to refine the scope and provide more specific, detailed discussions. The authors are encouraged to narrow the focus (Ex. by centering on one key component such as electrolytes or interfacial engineering) and to systematically summarize the major technical challenges, representative research progress, and future development directions within that area. At its current level of generality, the manuscript lacks the depth and critical insight expected from a review article and may not meet the journal’s publication standards. A more specific and focused narrative would greatly strengthen the clarity, academic value, and contribution of this work.

We modified our focus to have an increased discussion about cross-cutting developments, with a focus on how the battery technologies support each other. To do this, we provided a deeper analysis of each individual battery development process in addition to increasing the discussion on cross-cutting research.

The manuscript attempts to summarize recent research trends in multivalent ion batteries (MVIBs). However, it broadly covers multiple systems without focusing on any specific component or technical issue in sufficient depth. As a result, the review lacks a clear central theme and does not effectively present up-to-date research trends with analytical insight. For instance, the authors could have concentrated on a particular aspect such as the technical challenges associated with metallic anodes, the degradation mechanisms of cathode materials, or electrolyte engineering. Instead, the manuscript discusses each battery chemistry only in general terms, without detailed exploration of key issues. This lack of focus leads to inconsistencies, for example, dendrite formation is discussed for Zn-ion batteries but not for Mg-ion systems, even though both are known to experience such issues under certain conditions.

We attempted to improve these inconsistencies by having a more holistic analysis of each battery technology. We also made sure that our references were generally more up to date.

We added more discussion to tie Section 4 back into material in Section 3 to show how cross-cutting strategies are applied across abttery technologies.

We added more discussion and justification to support the roadmap. We also included a new table that better explains these trends.

Overall, the manuscript does not meet the standards expected of a well-structured review article. It neither provides a focused and critical analysis of the field nor presents a coherent narrative supported by representative literature. Therefore, I regret to state that I cannot recommend the manuscript for publication in its current form. While more detailed, section-by-section comments could be provided, the primary concerns lie in the overall direction, insufficient depth of analysis, and lack of specificity. For these reasons, I have chosen to focus on the general issues rather than detailed minor points.

We appreciate your comments. We have made significant changes to the paper based off your insights, and we're hoping that we addressed all of your concerns.

Reviewer 5 Report

Comments and Suggestions for Authors

This review comprehensively examines recent breakthroughs in Mg-, Zn-, Al-, and Ca-based battery chemistries, with a focus on overcoming barriers related to slow ion transport, limited reversibility, and electrode degradation. It discusses advances in aqueous and non-aqueous electrolyte formulations—including solvation shell engineering, interfacial passivation, and dual-zone ion transport—for their role in improving compatibility and cycling stability. The review also evaluates the role of cross-cutting insights from operando characterization techniques and AI-guided materials discovery in accelerating the development of multivalent ion batteries (MVIBs). Therefore, I think this manuscript could be accepted after some revisions.

What are the advantages and disadvantages of multivalent ion batteries compared to monovalent ion batteries (10.1002/ange.202423454, 10.1126/sciadv.adx7124)?
In Zn-ion batteries, interfacial engineering is used to suppress dendrite growth and side reactions. What is the mechanical stability and self-healing capability of these artificial interphase layers during actual long-term cycling? Are there any lifespan limitations?
What are the specific advantages of deep eutectic solvents (e.g., AlCl3-urea) used in Al-ion batteries compared to traditional chloroaluminate ionic liquids, in terms of electrochemical performance and environmental impact?
Is the Ca/Cl2 conversion reaction mechanism used in Ca-ion batteries applicable to other multivalent metal systems?
Multivalent ion batteries face compatibility issues between electrolytes and current collectors in practical applications (e.g., corrosion of aluminum foil in AlCl3). What novel current collectors or encapsulation strategies have been proposed to address these problems?
Some related works about multivalent ion batteries could be useful for discussion, such as Today 2023, 70, 93.

Author Response

Thank you for your review and your insights. We truly appreciate your thoughts and recommendations. We went through the paper and made major changes to it. The updated paper is significantly stronger and hopefully addresses all of your comments. Please see below for the point-by-point responses. Your comments are in red, and our responses are in black.

What are the advantages and disadvantages of multivalent ion batteries compared to monovalent ion batteries (10.1002/ange.202423454, 10.1126/sciadv.adx7124)?
We updated the paper to better capture the advantages and disadvantages of multivalent batteries, including more quantitative comparisons.
In Zn-ion batteries, interfacial engineering is used to suppress dendrite growth and side reactions. What is the mechanical stability and self-healing capability of these artificial interphase layers during actual long-term cycling? Are there any lifespan limitations?
We added significantly more material about Zn-ion batteries. This includes interfacial engineering, stability, and long-term cycling.
What are the specific advantages of deep eutectic solvents (e.g., AlCl3-urea) used in Al-ion batteries compared to traditional chloroaluminate ionic liquids, in terms of electrochemical performance and environmental impact?
We added material into the discussion Al-ion batteries to discuss the advantages of DES.
Is the Ca/Cl2 conversion reaction mechanism used in Ca-ion batteries applicable to other multivalent metal systems?
We added more discussion into the Ca-ion batteries section along with the cross-cutting technologies sections about the Ca/Cl2 conversion reaction mechanism.
Multivalent ion batteries face compatibility issues between electrolytes and current collectors in practical applications (e.g., corrosion of aluminum foil in AlCl3). What novel current collectors or encapsulation strategies have been proposed to address these problems?
We added more material throughout the paper to discuss these interface issues.
Some related works about multivalent ion batteries could be useful for discussion, such as Today 2023, 70, 93.
We weren't able to identify the references that you mentioned. But we did add a number of new works throughout the paper to make it more robust and comprehensive.

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

I appreciate the authors’ efforts in addressing the comments from the initial review. The revised manuscript shows clear improvement. However, there are still some mistakes to be corrected in the paper, especially on the references cited. I believe the paper will be suitable for publication after minor revisions.

Some references are cited corresponding to irrelevant content.
1. In line 40 (“multivalent ion batteries (MVIBs)…have emerged as promising next-generation systems”), references 3~5 are cited, whereas reference 3 and 4 are about sodium-ion batteries instead of multivalent ion batteries. What is the purpose of referencing these 2 papers here?
2. In lines 60~62 (“electrolyte innovations…have shown success in suppressing side reactions and improving cycling reversibility”), the reference on dual salt systems, ionic liquids and solvation tuned glymes need to be cited. The current reference paper is irrelevant.
3. In lines 73~75 (“Artificial solid-electrolyte interphases…have demonstrated success in controlling passivation and dendrite formation, particularly in Zn and Ca systems”), the reference is on Al-ion batteries, which is irrelevant.
4. For table 1 (line 116), reference 3, 5, 7 are cited. Reference 3 is on sodium-ion batteries, and reference 7 on potassium-ion batteries. What is the purpose of citing these papers in the table to compare properties of multivalent cations?
5. In line 222, reference 36 is irrelevant to the content discussing Zn-NTA.
Some statements and table are without supporting references.
1. In lines 66~68 (“SEI modification…has shown promise in improving reversibility and suppressing dendrite formation), reference needs to be added for SEI modification and rational electrolyte design.
2. For table 2, references 19~29 are cited, which only includes papers on Zn-ion batteries, Al-ion batteries and Ca-ion batteries. References on Mg-ion batteries are missing.
3. In lines 365~368, the authors state that “similar halide-based or conversion-type chemistries have been explored for magnesium and aluminum”, whereas the supporting reference paper is missing.
4. References need to be added for the content in lines 408~416, 423~430, 431~437.
In line 123, “large ionic radius” should be replaced by “large solvated ionic radius” for more rigid illustration.
Duplicate check needs to be done on the reference list. For example, reference 27 and 39 are the same.

Comments for author File: Comments.pdf

Author Response

Thank you for going through our paper and identifying these issues. In our previous submissions, we had multiple people writing and updating, and this caused a few issues with revision control. For this submission, one author took the lead and made sure that the citations were corrected throughout the paper. All of the issues with missing or incorrect references throughout the paper have been corrected. Please see below for by line responses to your comments (our replies are in black, your comments are in red):

Some references are cited corresponding to irrelevant content.
1. In line 40 (“multivalent ion batteries (MVIBs)…have emerged as promising next-generation systems”), references 3~5 are cited, whereas reference 3 and 4 are about sodium-ion batteries instead of multivalent ion batteries. What is the purpose of referencing these 2 papers here?
  Corrected. We have more appropriate papers for References 3-5
2. In lines 60~62 (“electrolyte innovations…have shown success in suppressing side reactions and improving cycling reversibility”), the reference on dual salt systems, ionic liquids and solvation tuned glymes need to be cited. The current reference paper is irrelevant.
  Corrected to have the appropriate citation.
3. In lines 73~75 (“Artificial solid-electrolyte interphases…have demonstrated success in controlling passivation and dendrite formation, particularly in Zn and Ca systems”), the reference is on Al-ion batteries, which is irrelevant.
  Corrected to have the appropriate citation here.
4. For table 1 (line 116), reference 3, 5, 7 are cited. Reference 3 is on sodium-ion batteries, and reference 7 on potassium-ion batteries. What is the purpose of citing these papers in the table to compare properties of multivalent cations?
  We were identifying the sources for the values in Table 1. References 3 and 7 have been replaced.
5. In line 222, reference 36 is irrelevant to the content discussing Zn-NTA.
  A relevant citation was added to replace Refrenece 36
Some statements and table are without supporting references.
1. In lines 66~68 (“SEI modification…has shown promise in improving reversibility and suppressing dendrite formation), reference needs to be added for SEI modification and rational electrolyte design.
  References added
2. For table 2, references 19~29 are cited, which only includes papers on Zn-ion batteries, Al-ion batteries and Ca-ion batteries. References on Mg-ion batteries are missing.
  References added
3. In lines 365~368, the authors state that “similar halide-based or conversion-type chemistries have been explored for magnesium and aluminum”, whereas the supporting reference paper is missing.
  References added
4. References need to be added for the content in lines 408~416, 423~430, 431~437.
  References added
In line 123, “large ionic radius” should be replaced by “large solvated ionic radius” for more rigid illustration.
Corrected.
Duplicate check needs to be done on the reference list. For example, reference 27 and 39 are the same.
We identified 3 additional duplicates when doing this check. Thank you for pointing that out.

Reviewer 4 Report

Comments and Suggestions for Authors

Some of the reference numbering appears misaligned or inconsistently formatted in the manuscript. Please carefully check and correct the citation numbering to ensure proper alignment and consistency. Moreover, in Section 4 (Cross-cutting strategies), it would be helpful to include representative research examples in the form of a figure to support the text, as the current text-only description may make it difficult for readers to fully grasp the content. Overall, the current version appears to be of publishable quality, provided that these minor formatting and presentation issues are addressed.

Author Response

Thank you for your reviews and insights. We have gone through the paper to make it a stronger work and to address your concerns. Please see below for our responses to your comments (our responses are in red):

Some of the reference numbering appears misaligned or inconsistently formatted in the manuscript. Please carefully check and correct the citation numbering to ensure proper alignment and consistency.

We had multiple authors working on the paper at the same time, and we failed to do a quality assurance check to make sure that the references stayed properly aligned. We have gone through the paper and checked it for consistency and alignment. We also made sure to check for duplications (we had a few references that were duplicated).

Moreover, in Section 4 (Cross-cutting strategies), it would be helpful to include representative research examples in the form of a figure to support the text, as the current text-only description may make it difficult for readers to fully grasp the content.

That is a great suggestion! We added a table that provides a summary of the results from the section.

Overall, the current version appears to be of publishable quality, provided that these minor formatting and presentation issues are addressed.