Fluorine-Free Single-Component Polyelectrolyte of Poly(ethylene glycol) Bearing Lithium Methanesulfonylsulfonimide Terminal Groups: Effect of Structural Variance on Ionic Conductivity

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

In this work, the authors synthesized poly(ethylene glycol) (PEG) with lithium methanesulfonylsulfonimide (LiMSSI) termini structure. The effect of the molecular weight of PEG, the modification ratio of terminal LiMSSI, the number of terminal LiMSSI groups, and the morphological arrangement of terminal LiMSSI groups on ionic conductivity has been studied. The glass transition temperature and electrochemical stability of the developed polymer electrolyte have also been determined. The study contributes to polymer electrolyte design. In this regard, it is recommended to be accepted with minor revision noted below.

1.       The differential scanning calorimetry (DSC) curves should be plotted and provided in the supplementary information for reference.

2.       The transference number, as an important property of polymer electrolyte, is suggested to be examined as well.

Author Response

Thank you for your valuable comments. We revised our manuscript according to your comments.

1.    The differential scanning calorimetry (DSC) curves should be plotted and provided in the supplementary information for reference.

We added DSC curves of the polyelectrolytes in SI (Figure S8).

2.       The transference number, as an important property of polymer electrolyte, is suggested to be examined as well.

We agree that the transference number is a very important property of single component polyelectrolytes. To be honest, we have tried to measure the transference numbers of our materials, but we could not obtain reproducible results due to our poor experience in preparing battery devices. We accordingly gave up including transference numbers in this work. As indicated in Conclusion, we will investigate the transference number with the new design of the materials. 

Reviewer 2 Report

Comments and Suggestions for Authors

Fluorine-free single component polyelectrolytes were developed by hybridization of lithium methanesulfonylsulfonimide (LiMSSI) moieties to poly(ethylene glycol) (PEG) derivatives with different morphologies, and the relationship between the structure and the ionic conductivity was investigated. The PEG-LiMSSI derivatives with one, two, and three LiMSSI end groups were prepared by concomitant Michael-type addition and lithiation of PEGs and N-methanesulfonylvinylsulfonimide. The ionic conductivity at 60 °C ranged from 1.8 × 10^–7 to 2.0 × 10^–4 S/cm. I recommend publishing after minor revisions.

 

1. Does this electrolyte need additional lithium salt after the anion is attached to the end of the PEG?

2. It is suggested here that an introduction and discussion of polymer electrolytes be added to the introduction (recommended citation ChemSusChem 2023, 16, e202202334)

3. Please provide sample preparation for NMR testing, as well as detailed test parameters and procedures.

Author Response

Thank you for your valuable comments. We revised our manuscript according to your comments.
 
1. Does this electrolyte need additional lithium salt after the anion is attached to the end of the PEG?
We emphasized that single component polyelectrolytes does not contain low-molecular weight lithium salts in Line 34 in the revised manuscript.

2.    It is suggested here that an introduction and discussion of polymer electrolytes be added to the introduction (recommended citation ChemSusChem 2023, 16, e202202334)
Thank you for your suggestion. We compared the designs and properties with those of single component polyelectrolytes without low-molecular weight salts or solvents in Introduction. The comparison with gel or quasi-solid electrolytes will be confusing. Instead, we emphasized that single component polyelectrolytes do not contain salts and solvents in Line 74 and 385.

3. Please provide sample preparation for NMR testing, as well as detailed test parameters and procedures.
The parameters and solvent were added. We are sorry that 1H and 7Li NMR spectra were taken using different spectrometers and revised the experimental section.