Analysis of Pressure Characteristics of Ultra-High Specific Energy Lithium Metal Battery for Flying Electric Vehicles

Round 1

Reviewer 1 Report

Scientists working at universities and research institutes conduct research and develop new types of traction batteries intended to power various types of wheeled, floating and flying vehicles. Traction batteries intended for flying vehicles must have better parameters, especially in the area of high energy capacity and low weight. Research on new types of batteries for electric vehicles will allow for increasing the range and time in the air of unmanned aerial vehicles and their use in civil aviation aircraft.

The article presents a high substantive level. The tests were planned and performed correctly. Appropriate research tools were used. All conclusions are justified by the research conducted. Despite this, the authors must make the following corrections to the content of the article:

1) The literature analyzed in the introduction is too poor. An additional 10 articles written by European and American scientists must be cited and analyzed. A lot of articles in this area are published in MDPI Batteries.

2) No reference to Figure 1 in the article. There is no description of Figure 1 in the article. There are no sources where the data for drawing Figure 1 comes from.

3) In Figure 2, mark and name the most important components of the experimental set.

4) NMC – no explanation of the abbreviation in the article. Make an explanation of the abbreviation the first time you use it, or make a list of all abbreviations at the end of the article.

5) SEI – no explanation of the abbreviation in the article. Make an explanation of the abbreviation the first time you use it, or make a list of all abbreviations at the end of the article.

6) Line 125 – unnecessary space. Delete.

7) Line 13 – double space. Delete. Please check and delete unnecessary and double spaces throughout the text of the article.

8) Line 142. SEM – no explanation of the abbreviation in the article. Make an explanation of the abbreviation the first time you use it, or make a list of all abbreviations at the end of the article.

9) SEM scanning – a short description of the device and its basic parameters should be included.

10) Line 237. During the charging process, because lithium ions participate in the deposition reaction on the electrode / electrolyte surface, the lithium ion in the electrolyte near the lithium metal electrode is rapidly consumed, converted into solid lithium and then deposited on the electrode surface. The sentence is too long and too complex. They need to be reformulated.

11) Line 244 – unnecessary space. Delete.

12) Figure 7 c) and d). If possible, please post drawings in better quality and resolution. Delete the vertical line in Figure 7 d).

13) The final conclusions should be extended to include the practical application of the research performed. Where and when they may apply.

14) The final conclusions should be extended to include directions for continuing the research that has already been started.

15) Throughout the article, the electronics aspect should be developed in several places, in line with the name of the publishing house. It can describe the pressure measurement and processing system in more detail.

Minor editing of English language required

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Manuscript ID: electronics- 2939711

Title: Analysis of pressure characteristics of ultra-high specific energy lithium metal battery for flying electric vehicles

General comments: In this article, the authors applied external pressure on lithium metal battery to inhibits the dendrite growth and improve the battery cycle life. Lithium metal as anode in lithium-ion battery is a big issue as it makes dendrite formation easily. So, people already move to solid state battery when then started using Lithium metal as a anode for high energy density system.  Author does not say anything about what battery they used in the manuscript. They have been saying it’s a Lithium metal battery, but the explanation and the experimental results look like it’s a Li-ion battery. Author needs to provide more clear information before it submitted to a journal for reviewing.

Comments:

1.     In the manuscript author mention “electron microscope scanning” it should be scanning electron microscope everywhere.

2.     Figure 1 does not mention in the manuscript.

3.     How did you get those number prediction in figure 1?

4.     In page 2: “…negative dendrite of lithium metal batteries, this paper uses a battery pressure measurement…” What is the meaning of negative dendrite here?

5.     In page 2: “…which may trigger chain reactions such as the rupture or failure of the SEI film on the surface, and eventually shorten the battery’s cycle life.” Is there really SEI formation at lithium metal surface?

6.     In page 3: “However, as the battery discharge proceeds, the lithium metal dendrites gradually grow on the surface of the negative electrode, causing the volume to expand inside the battery and the surface pressure to increase.” How dendrite grow during discharge process?

Minor English editing required. 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 3 Report

In this manuscript, the authors combined experimental and modeling methods to study the impact of external pressure on dendrite growth in lithium metal batteries. The reviewer would suggest publication after the following issues solved.

1.       Why use the application in flying cars, which haven’t been really released to the public yet, to justify the motivation of this research?

2.       Line 47, 53 and 55, remove the ‘And’ before the authors’ names.

3.       Figure 2a, the illustration is confusing as it shows gaps between the battery, sensor and the plates.

4.       Section 2.1, the experiments need to be described in much more details. For example, what are the battery specifics, how are the battery cycling performed etc.

5.       Line 90-100, add phrase like ‘as shown in Figure.3a’ to direct readers.

6.       Line 105-117, the authors did not provide enough evidence for their hypothesis.

Moderate editing of English language required

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Manuscript Title- Analysis of pressure characteristics of ultra-high specific energy lithium metal battery for flying electric vehicles

Journal- electronics

Manuscript id-electronics-2939711

Remarks to the Authors

The study explores the potential of lithium metal batteries for future flying electric vehicles, emphasizing their high theoretical specific capacity. Through pressure cycling tests and electron microscope scans, researchers demonstrate that amplifying initial preload delays battery failure and improves electrode surface structure. Further analysis using nonlinear phase field and force models reveals that increasing external pressure reduces dendrite length and migration curvature, leading to smoother and thicker lithium development. This decreases specific surface area, but ongoing cyclic charging and discharging require increased pressure to effectively inhibit dendrite growth due to decreased electrolyte diffusion coefficient and higher internal stress.

I appreciate the experiments conducted in this manuscript, however, several issues must be addressed.

#1: Firstly, expand eV-TOL before using abbreviations- I suppose it refers to “electric vertical takeoff and landing” if not, mention it properly in the manuscript.

#2: Line 53- Please start the sentence with either Zhang et al. or with another suitable word. Starting with “And” is not a proper way.

#3: The entire manuscript is poorly written and below standard, please write it properly.

#4: Line 80- SEI- is not the way to use. If abbreviations are used, they must be explained at the earlier somewhere inside the manuscript.

#5: Lines 73-74- poorly written, what does the author wish to explain, make it clear.

#6: English of the manuscript must be improved.

P.S. These comments in no way undermine the work presented here. However, they are just to enhance the quality of work and to raise the standard of the articles suitable for publication in electronics. Please consider these comments to better your present manuscript with a major revision and pinpoint the highlights to better represent the features of this research work.

Best wishes

Must be improved and is below standard.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Thank you so much for answering all questions and improving the manuscript content and quality. 

Minor editing required.

Reviewer 4 Report

Thank you for revising it

Minor editing is required.