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Creating oxygen-vacancies in MoO3-x nanobelts toward high volumetric energy-density asymmetric supercapacitors with long lifespan.
- Source :
- Nano Energy; Apr2019, Vol. 58, p455-465, 11p
- Publication Year :
- 2019
-
Abstract
- Abstract Herein, we present the synthesis of oxygen vacancies-rich α -MoO 3- x nanobelts through a novel defect-engineering strategy. The oxygen-vacancies could not only greatly increase the interlayer spacing and the electrical conductivity of MoO 3 , but also significantly enhance the electrochemical activity, which promotes faster charge storage kinetics. Meanwhile, to further facilitate the electron transfer and ion transport, a graphene nanomesh-carbon nanotube/MoO 3- x (GC/MoO 3- x) nanocomposite with three-dimensional sandwiched structure was fabricated, which displays high specific capacity up to 306 C g<superscript>−1</superscript> as well as high volumetric capacity of 692 C cm<superscript>−3</superscript>. Our fabricated asymmetric supercapacitor (ASC) with the GC/MoO 3- x and GC/MnO 2 nanocomposites as anode and cathode, respectively, exhibits an ultrahigh energy of 150 Wh kg<superscript>−1</superscript>, corresponding to an impressive volumetric energy density of 319 Wh L<superscript>−1</superscript>. Notably, both the gravimetric and volumetric energy densities are much higher than most of the previously reported metal oxide based ASCs in aqueous electrolytes. Furthermore, the ASC displays an ultra-long lifespan with 101% retention ratio after 30,000 cycles. The outstanding performances of GC/MoO 3- x composite render it a highly promising candidate for next-generation supercapacitors with both high energy and power densities in future applications, especially in greatly limited space. Graphical abstract fx1 Highlights • Oxygen vacancies-rich MoO 3- x is prepared through a novel defect-engineering strategy. • Oxygen-vacancies greatly increase the interlayer spacing, electrical conductivity and electrochemical activity of MoO 3. • High specific capacity up to 306 C g<superscript>−1</superscript> (692 C cm<superscript>−3</superscript>) is obtained. • An ultrahigh volumetric energy density of 319 Wh L<superscript>−1</superscript> is obtained, the highest value for aqueous supercapacitors up to date. • ASC displays an ultra-long lifespan with 101% retention ratio after 30,000 cycles. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 22112855
- Volume :
- 58
- Database :
- Supplemental Index
- Journal :
- Nano Energy
- Publication Type :
- Academic Journal
- Accession number :
- 135376883
- Full Text :
- https://doi.org/10.1016/j.nanoen.2019.01.071