Computational Study of Lithium Intercalation in Silicene Channels on a Carbon Substrate after Nuclear Transmutation Doping

Round 1

Reviewer 1 Report

1- The abstract addresses adequately "what the authors did" and "how they did it". But it falls short of  answering "what the results were" and "what the significance of the results are". In particular, what is the predicted effect of doping on stress and on battery performance?

2- Can the authors provide any experimentally observed pieces of evidence corroborating their predictions?

2- To the benefit of the readers, the settings of the simulation cell of the classical MD should be summarized in a Table, i.e. number of atoms of each sheet, total number of atoms in the cell, cell dimensions, simulation duration and so on.

3- The authors have calculated the diffusion coefficients (D). What is the significance of D on stresses and the overall performance of the battery?

4- What is the equation used to calculate the density profile (of Li)? and what is the duration of the measurement of this quantity (averaging)?

5- How did the authors fit the parameters for the pair potential related to Li-Li and Li-X (X=Si, C etc.) interactions? 

Author Response

Response to Reviewer 1

Point 1. The abstract addresses adequately "what the authors did" and "how they did it". But it falls short of answering "what the results were" and "what the significance of the results are". In particular, what is the predicted effect of doping on stress and on battery performance?

Response 1. The abstract has undergone significant changes. Now it reflects not only the results but also their significance, including the predictive effect of doping on the LIB capacity and recharge rate.

Point 2. Can the authors provide any experimentally observed pieces of evidence corroborating their predictions?

Response 2. There are a sufficient number of experimental works devoted to the doping of bulk silicon and its macroscopic films with phosphorus, but there are no studies on the doping of silicene (films with a thickness of one or more atomic sizes). This is partly due to the fact that a little time has passed since the discovery of silicene, the optimal technologies for its preparation are still being developed. Nevertheless, indirect evidence of the usefulness of doping silicene used as an anode material is included in the article. So the present version of the article contains a fragment:

It was experimentally established that the hardness of silicon wafers according to Vickers increases by 1.2 times after its strong doping with phosphorus [45]. This result is consistent with our average 4.2% increase in the binding energy of lithium with the substrate after doping of silicene with phosphorus. The binding energy increases with closer contact of Li atoms with the silicic wall of the channel, which is possible when the wall becomes more rigid.

Point 3. To the benefit of the readers, the settings of the simulation cell of the classical MD should be summarized in a Table, i.e. number of atoms of each sheet, total number of atoms in the cell, cell dimensions, simulation duration and so on.

Response 3. For a more convenient reading of the article, Table 4 has been created, which contains all the used simulation settings.

Point 4. The authors have calculated the diffusion coefficients (D). What is the significance of D on stresses and the overall performance of the battery?

Response 4. To clarify the significance of the diffusion coefficient of lithium for charge/discharge and the general characteristics of the battery, the following fragment is included in the article:

Low diffusion barriers of Li, suggests that silicene on a substrate has an increased charge/discharge rate [40]. Thus, higher values of the coefficient D are necessary to increase the rate of cycling. However, an excessive increase in the self-diffusion coefficient of lithium ions сaused, for example, by strong heating can lead to the occurrence of significant stresses in silicene sheets, which will lead to the destruction of the material.

Point 5. What is the equation used to calculate the density profile (of Li)? and what is the duration of the measurement of this quantity (averaging)?

Response 5. A fragment has been inserted into the text of the article explaining how the lithium density profile was calculated and how long this measurement was.

The profile of the Li atom distribution density in the silicene channel was calculated as follows. The total volume of the channel was divided into identical elementary volumes. Further, how many Li atoms (in the completely lithiated systems) belong to such an elementary volume were estimated. This procedure was performed along with the axes ox and oz (horizontal and vertical distribution density).  The density profile reflects the final filling of the channel with lithium.

Point 6. How did the authors fit the parameters for the pair potential related to Li-Li and Li-X (X=Si, C, etc.) interactions? 

Response 6. A sentence was added to the text explaining how the parameters were selected to describe the interactions Li-Li and Li-X, where X = Si, C, P, N.

Also, according to formulas (3), the interactions Li-Li and Li-X were calculated, where X = Si, C, P, N.

We added 2 additional references in the article.

Author Response File: Author Response.docx

Reviewer 2 Report

Galashev et al. demonstrated excellent possibilities for using P-doped silicene as electrode material in a lithium ion batteries via DFT calculations. Their finding will provide suggestions for the design of silicence based anode. To present a very high impact research paper, I suggest some revisions should be done.

Author Response

Response to Reviewer 2

Point 1. The language of English should be improved. The figures 7, 8 and 9 should be combined to one. 

Response 1. In the present version of the article, figures 7, 8, and 9 are combined into one figure 7.

All corrections made are highlighted in yellow.

We corrected and improved the English language in the text of the article.

Author Response File: Author Response.docx