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Core–Shell Nitrogen‐Doped Carbon Hollow Spheres/Co 3 O 4 Nanosheets as Advanced Electrode for High‐Performance Supercapacitor
Author(s) -
Liu Tao,
Zhang Liuyang,
You Wei,
Yu Jiaguo
Publication year - 2018
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201702407
Subject(s) - supercapacitor , materials science , calcination , electrode , composite number , carbon fibers , chemical engineering , nanorod , capacitance , hydrothermal synthesis , power density , nanotechnology , hydrothermal circulation , composite material , catalysis , organic chemistry , chemistry , power (physics) , physics , quantum mechanics , engineering
Abstract Co 3 O 4 /nitrogen‐doped carbon hollow spheres (Co 3 O 4 /NHCSs) with hierarchical structures are synthesized by virtue of a hydrothermal method and subsequent calcination treatment. NHCSs, as a hard template, can aid the generation of Co 3 O 4 nanosheets on its surface; while SiO 2 spheres, as a sacrificed‐template, can be dissolved in the process. The prepared Co 3 O 4 /NHCS composites are investigated as the electrode active material. This composite exhibits an enhanced performance than Co 3 O 4 itself. A higher specific capacitance of 581 F g −1 at 1 A g −1 and a higher rate performance of 91.6% retention at 20 A g −1 are achieved, better than Co 3 O 4 nanorods (318 F g −1 at 1 A g −1 and 67.1% retention at 20 A g −1 ). In addition, the composite is employed as a positive electrode to fabricate an asymmetric supercapacitor. The device can deliver a high energy density of 34.5 Wh kg −1 at the power density of 753 W kg −1 and display a desirable cycling stability. All of these attractive results make the unique hierarchical Co 3 O 4 /NHCS core–shell structure a promising electrode material for high‐performance supercapacitors.