Issue 42, 2018

Hybrid NiO–CuO mesoporous nanowire array with abundant oxygen vacancies and a hollow structure as a high-performance asymmetric supercapacitor

Abstract

High specific capacity as well as good cycling stability are crucial for practical applications of supercapacitors, but actually the specific capacitances of transition metal oxide-based electrodes are still far below their theoretical predictions, and their cycling stabilities cannot satisfy the commercial standard due to intrinsically poor electronic conductivity and volume structural changes during charging/discharging processes. Here, we report the synthesis of a hybrid NiO–CuO mesoporous nanowire array with abundant oxygen vacancies which constructs a three-dimensional (3D) hollow architecture via a facile hydrothermal method and subsequent annealing. Compared to single-phase NiO or CuO, the increased O-vacancies on the NiO–CuO hybrid nanowires probably arising from a high number of lattice defects can promote their electronic conductivity, as revealed by XPS O 1s spectra, EPR characterization and HRTEM images. In addition, the 3D hollow structure together with mesoporous nanowires composed of alternately linked NiO and CuO nanocrystals can relax strain stress either in a hollow 3D structure or along a one-dimensional (1D)-direction nanowire, which not only provides a fast diffusion pathway for electrolyte ions and a high surface area with more active sites, but also helps to maintain the structural integrity during charge/discharge cycles. Therefore, the as-prepared NiO–CuO@Ni foam has a high areal capacitance of 4.35 F cm−2 and also a very high specific capacitance of 1450.8 F g−1 at a current density of 2 mA cm−2. Further, it can be utilized directly as a binder-free positive electrode, and assembled with a negative electrode based on a 3D porous graphene hydrogel (PGH) to construct an asymmetric supercapacitor, which shows a wide potential window of 1.6 V and an outstanding cycling stability of 90.4% capacitance retention after 5000 charge/discharge cycles.

Graphical abstract: Hybrid NiO–CuO mesoporous nanowire array with abundant oxygen vacancies and a hollow structure as a high-performance asymmetric supercapacitor

Supplementary files

Article information

Article type
Paper
Submitted
25 Aug 2018
Accepted
04 Oct 2018
First published
06 Oct 2018

J. Mater. Chem. A, 2018,6, 21131-21142

Hybrid NiO–CuO mesoporous nanowire array with abundant oxygen vacancies and a hollow structure as a high-performance asymmetric supercapacitor

Z. Fang, S. U. Rehman, M. Sun, Y. Yuan, S. Jin and H. Bi, J. Mater. Chem. A, 2018, 6, 21131 DOI: 10.1039/C8TA08262F

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