Issue 9, 2019

Graphene quantum dot induced tunable growth of nanostructured MnCo2O4.5 composites for high-performance supercapacitors

Abstract

Achieving an optimal surface structure and adequate carbon distribution is an important criterion for transition metal oxide/carbon composites targeted for supercapacitor applications. In this study, a one-step hydrothermal reaction is developed to incorporate graphene quantum dots (GQDs) and MnCo2O4.5 with GQDs serving as both a conductive filling material and structure inducing agent. The process is fine-tuned based on GQD quantities to generate various morphologies including nanospheres, nanoneedles and nanoarrays. And a mechanism is proposed to explain the roles of GQDs in triggering the structural transformation. Among the different structures, the nanoneedle composites (denoted as MCO-40 GQDs) exhibit an apparent porous structure and even GQD distribution, which establishes a conductive network that provides excellent charge transfer capability for optimal electrochemical performances. As a result, the MCO-40 GQD nanoneedle electrode delivers the largest capacitance of 1625 F g−1 at 1 A g−1, which is four times higher than the capacitance of a pure MnCo2O4.5 nanosphere electrode (368 F g−1 at 1 A g−1). Moreover, the asymmetric supercapacitor fabricated with MCO-40 GQDs and reduced graphene oxide exhibits long cycle stability and a high energy density of 46 Wh kg−1 at a power density of 66 W kg−1, surpassing all previously reported capacitive devices based on MnCo2O4.5. Overall, this study illustrates the exciting roles of GQDs in material synthesis as a structure inducing agent and provides for the first time a reference for constructing MnCo2O4.5 based advanced nanomaterials with various shapes for energy storage applications.

Graphical abstract: Graphene quantum dot induced tunable growth of nanostructured MnCo2O4.5 composites for high-performance supercapacitors

Supplementary files

Article information

Article type
Paper
Submitted
01 Jūn. 2019
Accepted
19 Jūl. 2019
First published
22 Jūl. 2019

Sustainable Energy Fuels, 2019,3, 2499-2508

Graphene quantum dot induced tunable growth of nanostructured MnCo2O4.5 composites for high-performance supercapacitors

M. Zhang, W. Liu, R. Liang, R. Tjandra and A. Yu, Sustainable Energy Fuels, 2019, 3, 2499 DOI: 10.1039/C9SE00341J

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements