Small nitrogen-doped carbon dots as efficient nanoenhancer for boosting the electrochemical performance of three-dimensional graphene

Gang Yuan; Xiao Zhao; Yeru Liang; Lin Peng; Hanwu Dong; Yong Xiao; Chaofan Hu; Hang Hu; Yingliang Liu; Mingtao Zheng

doi:10.1016/j.jcis.2018.10.096

Small nitrogen-doped carbon dots as efficient nanoenhancer for boosting the electrochemical performance of three-dimensional graphene

J Colloid Interface Sci. 2019 Feb 15:536:628-637. doi: 10.1016/j.jcis.2018.10.096. Epub 2018 Oct 30.

Authors

Gang Yuan¹, Xiao Zhao², Yeru Liang¹, Lin Peng¹, Hanwu Dong³, Yong Xiao³, Chaofan Hu¹, Hang Hu¹, Yingliang Liu⁴, Mingtao Zheng⁵

Affiliations

¹ College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China.
² Guangdong Provincial Engineering Technology Research Center for Optical Agriculture, Guangzhou 510642, China.
³ College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China; Guangdong Provincial Engineering Technology Research Center for Optical Agriculture, Guangzhou 510642, China.
⁴ College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China; Guangdong Provincial Engineering Technology Research Center for Optical Agriculture, Guangzhou 510642, China. Electronic address: tliuyl@scau.edu.cn.
⁵ College of Materials and Energy, South China Agricultural University, Guangzhou 510642, China; Guangdong Provincial Engineering Technology Research Center for Optical Agriculture, Guangzhou 510642, China. Electronic address: mtzheng@scau.edu.cn.

PMID: 30391905
DOI: 10.1016/j.jcis.2018.10.096

Abstract

As a new class of zero-dimensional carbon nanomaterials, carbon dots have triggered intensive research interest in various fields. However, the low surface area, hydrophilicity, and agglomeration characteristics limit their applications in energy storage fields. Herein, we demonstrate that nitrogen-doped carbon dots can be employed as efficient nanoenhancer to boost the electrochemical performance of three-dimensional graphene. The as-prepared materials exhibit an interconnected framework with abundant oxygen- and nitrogen-containing functional groups, which enable fast penetration and transport of electrolyte ions and provide more active sites and electric conductivity. Employed as binder-free electrode for supercapacitors, the resultant materials present high specific capacitance (338 F g^-1) and areal capacitance (604 μF cm^-2) at a current density of 0.5 A g^-1, which is much higher than that of pristine three-dimensional graphene (190 F g^-1, and 114 μF cm^-2), with an enhancement of 78% and 430%, respectively. Moreover, superior long-term cycling stability (94% of capacitance retention after 20 000 charging/discharging cycles at 10 A g^-1) as well as improved electric conductivity can also be achieved. These results certify that nitrogen-doped carbon dots can be applied as nanobooster to comprehensively improve the performance of graphene for high-performance electrochemical energy storage.

Keywords: Graphene; Nanoenhancer; Nitrogen-doped carbon dots; Supercapacitors.