Single-source formation and assessment of nitrogen-doped graphitic spheres for lithium- and sodium-ion batteries.

Optimisation of the annealing time for the fabrication of nitrogen-doped graphitic-spheres (NDGSs), formed from a nitrogen-functionalised aromatic precursor at 800 °C, to give high nitrogen doping has been performed. Thorough analysis of the NDGSs, approximately 3 μm in diameter, pinpointed an optimum annealing time of 6 to 12 hours to obtain highest nitrogen content at the surface of the spheres (reaching a stoichiometry of around C3N at the surface and C9N in the bulk), with the quantity of sp2 and sp3 surface nitrogen varying with annealing time. The results suggest that changes in the nitrogen dopant level occur through slow diffusion of the nitrogen throughout the NDGSs, along with reabsorption of nitrogen-based gases produced during annealing. A stable bulk nitrogen dopant level of 9% was revealed in the spheres. The NDGSs performed well as anodes in lithium-ion batteries, providing a capacity of up to 265 mA h g-1 at a charging rate of C/20, but did not perform well in sodium-ion batteries without the use of diglyme, consistent with the presence of graphitic regions, but with low internal porosity.

Description

Acknowledgements: The authors acknowledge funding from EPSRC grant No. EP/L016087/1 (EPSRC Centre for Doctoral Training in Graphene technologies). The authors acknowledge EPSRC Underpinning Multi-User Equipment Call (EP/P030467/1) for use of the Talos F200X G2 TEM. The authors would like to acknowledge for the collection of XPS data the EPSRC National Facility for XPS (‘HarwellXPS’) operated by Cardiff University and UCL, under contract No. PR16195. We extend our thanks to Keith Parmenter (Technical Services, Yusuf Hamied Department of Chemistry, University of Cambridge) for his assistance with glass blowing, and to Nigel Howard (Microanalysis, Yusuf Hamied Department of Chemistry, University of Cambridge) for performing the ICP-OES experiments. CPG and DSW would like to acknowledge the Faraday Institution FIRG018 Next Generation Na-ion Batteries for funding.

Keywords

34 Chemical Sciences, 3406 Physical Chemistry

Journal Title

RSC Adv

Journal ISSN

2046-2069
2046-2069

Volume Title

13

Publisher

Royal Society of Chemistry (RSC)

Publisher DOI

https://doi.org/10.1039/d3ra01409f

Rights and licensing

Except where otherwised noted, this item's license is described as Attribution 4.0 International

Sponsorship

Faraday Institution (via University Of St Andrews) (NEXGENNA)
Faraday Institution (NEXGenna)
Faraday Institution (via University Of St Andrews) (NEXGenna)
Engineering and Physical Sciences Research Council (EP/L016087/1)
Engineering and Physical Sciences Research Council (EP/P030467/1)

The authors acknowledge funding from EPSRC grant No. EP/L016087/1 (EPSRC Centre for Doctoral Training in Graphene technologies). The authors acknowledge EPSRC Underpinning Multi-User Equipment Call (EP/P030467/1) for use of the Talos F200X G2 TEM. The authors would like to acknowledge for the collection of XPS data the EPSRC National Facility for XPS (‘HarwellXPS’) operated by Cardiff University and UCL, under contract No. PR16195. We extend our thanks to Keith Parmenter (Technical Services, Yusuf Hamied Department of Chemistry, University of Cambridge) for his assistance with glass blowing, and to Nigel Howard (Microanalysis, Yusuf Hamied Department of Chemistry, University of Cambridge) for performing the ICP-OES experiments. CPG and DSW would like to acknowledge the Faraday Institution FIRG018 Next Generation Na-ion Batteries for funding.

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