Surface Modification of Ga-Doped-LLZO (Li₇La₃Zr₂O₁₂) by the Addition of Polyacrylonitrile for the Electrochemical Stability of Composite Solid Electrolytes

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript designs a three-layer composite solid electrolyte consisting of a PVDF-HFP-based polymer electrolyte, a composite electrolyte with a high LGLZO ceramic filler ratio, and a PVDF-HFP-based polymer electrolyte. The interface of three-layer composite solid electrolyte impregnated with a plastic crystal electrolyte, respectively. The authors mentioned that the introduction of succinonitrile can improve battery performance, but it also leads to gelation during the mixing of succinonitrile and LGLZO, leading to interface side reactions. To this end, the author introduced polyacrylonitrile to alleviate the above problems. Among them, the -C≡N in PAN is more likely to react with the La in LGLZO, thus effectively preventing the nitrile group in succinonitrile from reacting with LGLZO and producing polymerization.

First of all, the composite solid electrolyte prepared in this paper lacks novelty and the logic of the paper is confused. And the battery and electrolyte system are too complex, some data did not give reasonable explanations.

Secondly, most of the characterizations and tests in this paper are basic and lack some investigation of mechanism. It is recommended to add some related tests, for example, 1) EDS element image of a cross-sectional view of the three-layer composite solid electrolyte (to ensure that it can be clearly seen whether the elements of the three-layer structure are evenly distributed and whether the three layers are tightly connected); 2) Use NMR spectra to further characterize the viewpoint mentioned in the article: "PAN blocks the polymerization of SCN through a cyclization process involving La-ions, which occurs more rapidly than SCN polymerization."; 3) It is recommended to add some ex-situ characterization of lithium and electrolytes.

Hence, we recomment a major revisions and some minor issues are  also listed as follows:

1. The notes of the diagrams should be unified, for example, the conversion between "CSE" and "g-PCE" is not accepted.

2. The title of Section 2.2 is "Preparation of LGLZO green sheets", but the following paragraph only describes the configuration of tape slurry, without the preparation method of LGLZO green sheets.

3. FEC solvent is mentioned in section 2.3, but the dosage and effect are not specified, and it is not mentioned elsewhere. The specific dosage and action should be given. Or whether it was a typo.

4. Some of the characterization methods mentioned in material characterization in Section 2.5 were not tested in the manuscript provided by the author. For example, the energy-dispersive spectrometer test. Please check that all of the mentioned characterization methods provide test results.

5. The end of section 2.6 mentions the introduction of a PVA-CN gel polymer at the interface between the positive electrode and the electrolyte, but only cites a review paper without giving a specific description. Even if it is not the main research content of this paper, it should give corresponding explanation, or cite proper previous research work.

6. We know that multi-layer pouch cell with all-solid-state electrolyte is not easy to implement. According to our experience, the pouch cell batteries given in the article have no less than one layer. Please provide a more detailed description of the pouch cell. And check whether the captions or the order of pictures in Figures 8a and 8b are incorrect. For example, is the “mAh” in Figure 8b wrong?

Comments on the Quality of English Language

Language issue is minor.

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Reviewer 2 Report

Comments and Suggestions for Authors

Please see attached

Comments for author File: Comments.docx

Comments on the Quality of English Language

Minor editing of English language required

Author Response

Please see the attachment.

Author Response File: Author Response.docx

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have addressed my previous comments, thus the current vesion can be accepted now.