Auger- and X-ray Photoelectron Spectroscopy at Metallic Li Material: Chemical Shifts Related to Sample Preparation, Gas Atmosphere, and Ion and Electron Beam Effects
Round 1
Reviewer 1 Report
This paper entitled "Auger- and X-ray photoelectron spectroscopy at metallic Li-material: chemical shifts related to sample preparation, gas atmosphere and ion- and electron-beam effects" deals with technical challenges when using XPS, AES and sputtering, to characterize Li surfaces. The effect of exposure and sputtering time, surface area and atmosphere when exposed under e-, ion or X-ray beam on the reference C contamination C1s binding energy value and/or the outermost layer composition has been extensively studied.
This paper deserves to be published in the journal “batteries” after correcting lots of typing mistakes (At least in Line 45,55,60,162,173,183,241, 377).
Author Response
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Author Response.pdf
Reviewer 2 Report
The manuscript reports about a thorough investigation of fundamental interest for the lithium ion battery specialist. Some flaws and errors require attention and correction, please see annotated file.
Comments for author File: Comments.pdf
Author Response
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Author Response File: Author Response.pdf
Reviewer 3 Report
The manuscript reports on an interesting study on the surface chemistry of Li metal. This is timely and topical. The surface of reactive metal has been known to be complicated, particularly when subject to dynamic electrochemical cycling.
In my opinion, it is suitable for publication in the Journal after the authors address the concerns as follows.
The paper reports quite a large amount of interesting data. I would suggest that the authors make one simple summary Figure (or even a cartoon?) to give the readers a strong/quick impression and convey the central messages.
The authors carefully controlled the environment where the Li metal was cut. It may be also worthwhile to intentionally study normal intact Li surfaces. As summarized in the Review (DOI: 10.1021/acs.chemrev.7b00115), different species could be present on the surface and influence the electrochemical cycling of Li metal anode in battery. Experimentally, it would be interesting to see the SEI developed after immersing the Li metal foil into an electrolyte. The authors may give a discussion on this point and possibly perform some future studies (beyond this present work).
Is there a way to probe the spatial homogeneity of the surface layer? It’s known that heterogeneous SEI gives rise to non-uniform Li growth upon Li deposition.
Beyond traditional Li-metal anodes, other metal anodes are also growing fast. I believe the impact of the paper could be further improved if the author could briefly bring out this point (i.e. the rapid growth of multiple types of batteries) in the Introduction section. Here are some key relevant references for consideration: Zn: 10.1126/sciadv.abe0219; 0.1126/sciadv.abb1122; Al: 10.1038/nature14340.
I strongly suggest that the authors strengthen the Abstract and the Conclusion sections by bringing out the key scientific information obtained from the in-depth characterization work. In addition to the instrumentational merits, a reader from the battery community may want to see how this work could be relevant to their studies. Put alternatively, how this work could be used to guide battery research?
Minor issue: pg 19 line 520: “a perfect tool”. The statement of being perfect doesn’t sound scientific. I would suggest the authors change to—for example— “a powerful tool”
Author Response
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Author Response File: Author Response.pdf
Reviewer 4 Report
Submitted manuscript is dedicated to interesting and well timed topic related to the development of experimental methods for advanced characterisation of battery materials surface. Quality of manuscript is very good. Therefore, I suggest to publishing the reviewed manuscript after minor revision in accordance with my comments below.
Lines 49: I disagree that “in the Li-battery community it plays up to now no important role” since recently several cryogenic techniques have been reported (http://smeng.ucsd.edu/wp-content/uploads/Cryogenic-Focused-Ion-Beam-Characterization-of-Lithium-Metal-Anodes.pdf etc.). Please edit the sentence.
Lines 133-138. Please provide more information about experimental part (glove box model and design of transfer channels, scheme and/or photos of whole setup and it parts, material of knife, chemical analysis sheet of used Li metal etc.).
Line 201. Please describe in detail what is exact difference between A-nat and B-nat samples.
Figures 1-2-3-4-6-7-8-9-11-12. It is difficult to attribute spectra to concrete sample. Please add corresponding labels.
Line 264. I do not understand meaning of “[XXX] – values for Li2O2“. Please explain.
Line 377. Please remove “XP” at the beginning of the phrase.
Line 411. Please explain why it is obvious that the carbonate is converted to Li2O due to sputtering?
Line 497-499. Please cite recent reports about XPS spectra misinterpretation (e.g. https://www.sciencedirect.com/science/article/abs/pii/S0169433220324569, etc.).
Author Response
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Author Response File: Author Response.pdf
Reviewer 5 Report
The authors prepared samples with different surface characteristics by changing the environment in which lithium metal exists. Through the XPS test, the surface element spectra of these samples were obtained. In addition, the differences of AE spectra under different test areas were also studied. Generally speaking, this manuscript studies the influence of different sample preparation methods and test methods on the XPS test results. Thus, the work can be published in Batteries after minor revisions. Several problems are required to be addressed before its publication.
- The peak shape of adsorbed carbon (carbon contamination) in Figure 1c is a bit strange. It is recommended that the authors should test the adsorbed carbon with a standard sample and add it to the figure.
- In Fig. 2c, the adsorbed carbon in C-air is less than that in C-intro. Even after the intensity is normalized, the intensity should be higher (more adsorbed carbon).
- The signal-to-noise ratio of the Ar 2p peak in Figure 3d is not good. The authors can get a better spectrum by reducing the step size and increasing the dwell time.
- The abscissa in the schematic diagram, the authors gave two definitions, namely Binding energy and Kinetic energy. However, in the manuscript, the authors only write out the value of photoelectron energy without specifying whether it is binding energy or kinetic energy.
- In Fig. 2, Fig. 3, Fig. 4, and Fig. 6, the annotation of the curve in the black frame should be the same as the color of each curve.
- The authors should carefully check the manuscript, avoiding unnecessary spelling and grammatical errors.
Author Response
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Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
the text has been correctly modified and the new figure summarizes well the different results from XPS and Auger.
Reviewer 2 Report
Yes, these publications are certainly scientifically sound published in well-known journals with peer-review.
Reviewer 4 Report
Overall quality of the revised manuscript has been improved. Therefore, I suggest publishing of the manuscript in the presented form.
Reviewer 5 Report
The manuscript could be accepted
