# Novel Q-Carbon Anodes for Sodium-Ion Batteries
## 4 Conclusions  
The use of Q-carbon is an interesting pathway for making sodium-ion battery anodes with a high ICE and high capacity and stability. The higher amount of disordered carbon in Q1 with a low surface area is beneficial for fast sodium intercalation/deintercalation but lacks the necessary cycling stability, whereas the lower amount of disordered carbon in Q2 with a high surface area leads to a low ICE and low capacity but with much improved cycling stability, which all can be traced back to the thinner and stable SEI layers. Further tuning of process parameters can be performed to find the optimum particle size and distribution, surface area, and porosity. Our initial hypothesis was that we would observe a different storage mechanism due to the diamond tetrahedra structure of the carbon. However, the disordered structure and micro- and meso-pores in the carbon dominate the sodium storage mechanism. This could be due to the high thermodynamic barrier for sodium bonding with the diamond tetrahedra structure and needs to be explored further. **Supplementary Materials:** The following supporting information can be downloaded at: [[https://www.mdpi.com/article/10.3390/app142210679/s1](https://www.mdpi.com/article/10.3390/app142210679/s1)]([https://www.mdpi.com/article/10.3390/app142210679/s1](https://www.mdpi.com/article/10.3390/app142210679/s1)), Figure S1: XRD patterns and Raman for Q1 and Q2 carbon; Figure S2: Relative pressure (P/Po) vs quantity adsorbed (mmol/g STP) for (a) Q1  
Figure 3: XPS spectra C1s (**a**,**b**) and F1s (**c**,**d**) for Q1 and Q2 carbon, respectively. and (b) Q2 carbon; Figure S3: Particle size distribution of Q1 and Q1 carbon powder; Figure S4: The XPS spectra for Q1 and Q2 carbon; Figure S5: (a) SEM image of Q1 carbon; (b) 10X zoomed SEM images of Q1 carbon; (c) SEM image of Q2 carbon; and (d) 5X zoomed SEM image of Q2 carbon; Figure S6: Electrochemical Impedance Spectroscopy (EIS) for (a) Q1; and (b) Q2. Table S1: Table outlines the ICE, final capacity, and capacity retention of Na half cells for Q1 and Q2 carbon; Table S2: XPS data fitting for Q1 and Q2 carbon. Sodium disk making: Sodium metal billets were first cleaned with paper towels to wipe off the residual kerosene oil. The billets were then flattened with a soft mallet and cleaned/polished with a blade to remove any surface oxidation. The flattened mass of sodium metal was then sent through a pasta maker with the largest inter-gap distance between the rolls. The gap was reduced after every subsequent pass through the rollers until a uniform flat sheet of sodium metal 0.4 mm thick was achieved. Circular disks were then punched out of the flat sheet to be used as positive electrodes. Conceptualization, J.N. and M.P.P. ; methodology, S.P.P., S.S., X.-G.S., J.N. and M.P.P. ; validation S.P.P., S.S.S., X.-G.S., J.N. and M.P.P. ; formal analysis, S.P.P., S.S., X.-G.S., J.N. and M.P.P. ; data curation, S.P.P., S.S., A.G., H.M.M.III and X.-G.S. ; writing--original draft preparation, S.P.P. and S.S.S. ; writing--review and editing, S.P.P., S.S.S., A.G., H.M.M.III, X.-G.S., J.N. and M.P.P. ; supervision, X.-G.S., J.N. and M.P.P. ; project administration, J.N. and M.P.P. ; funding acquisition, J.N. and M.P.P. All authors have read and agreed to the published version of the manuscript. This research was supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division. This manuscript has been authored by UT-Battelle, LLC under Contract No. DEAC05-00 OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes.