Patching laser-reduced graphene oxide with carbon nanodots

Volker Strauss; Mit Muni; Arie Borenstein; Bolortuya Badamdorj; Tobias Heil; Matthew D Kowal; Richard Kaner

doi:10.1039/c9nr01719d

Patching laser-reduced graphene oxide with carbon nanodots

Nanoscale. 2019 Jul 14;11(26):12712-12719. doi: 10.1039/c9nr01719d. Epub 2019 Jun 26.

Authors

Volker Strauss¹, Mit Muni², Arie Borenstein³, Bolortuya Badamdorj⁴, Tobias Heil⁴, Matthew D Kowal², Richard Kaner⁵

Affiliations

¹ Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, USA. kaner@chem.ucla.edu and Max Planck Institut für Kolloid - und Grenzflächenforschung Am Mühlenberg 1, 14476 Potsdam, Germany. volker.strauss@mpikg.mpg.de.
² Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, USA. kaner@chem.ucla.edu.
³ Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, USA. kaner@chem.ucla.edu and Chemistry Department, Ariel University, Ariel, Israel.
⁴ Max Planck Institut für Kolloid - und Grenzflächenforschung Am Mühlenberg 1, 14476 Potsdam, Germany. volker.strauss@mpikg.mpg.de.
⁵ Department of Chemistry and Biochemistry and California NanoSystems Institute, University of California, Los Angeles (UCLA), Los Angeles, CA, USA. kaner@chem.ucla.edu and Department of Materials Science and Engineering, UCLA, Los Angeles, CA, USA.

PMID: 31241092
DOI: 10.1039/c9nr01719d

Abstract

Three-dimensional graphenes are versatile materials for a range of electronic applications and considered among the most promising candidates for electrodes in future electric double layer capacitors (EDLCs) as they are expected to outperform commercially used activated carbon. Parameters such as electrical conductivity and active surface area are critical to the final device performance. By adding carbon nanodots to graphene oxide in the starting material for our standard laser-assisted reduction process, the structural integrity (i.e. lower defect density) of the final 3D-graphene is improved. As a result, the active surface area in the hybrid starting materials was increased by 130% and the electrical conductivity enhanced by nearly an order of magnitude compared to pure laser-reduced graphene oxide. These improved material parameters lead to enhanced device performance of the EDLC electrodes. The frequency response, i.e. the minimum phase angle and the relaxation time, were significantly improved from -82.2° and 128 ms to -84.3° and 7.6 ms, respectively. For the same devices the specific gravimetric device capacitance was increased from 110 to a maximum value of 214 F g^-1 at a scan rate of 10 mV s^-1.