title: Co@Co₃O₄ core-shell three-dimensional nano-network for high-performance electrochemical energy storage.
abstract: An alternative routine is presented by constructing a novel architecture, conductive metal/transition oxide (Co@Co3O4) core-shell three-dimensional nano-network (3DN) by surface oxidating Co 3DN in situ, for high-performance electrochemical capacitors. It is found that the Co@Co3O4 core-shell 3DN consists of petal-like nanosheets with thickness of <10 nm interconnected forming a 3D porous nanostructure, which preserves the original morphology of Co 3DN well. X-ray photoelectron spectroscopy by polishing the specimen layer by layer reveals that the Co@Co3O4 nano-network is core-shell-like structure. In the application of electrochemical capacitors, the electrodes exhibit a high specific capacitance of 1049 F g(-1) at scan rate of 2 mV/s with capacitance retention of ~52.05% (546 F g(-1) at scan rate of 100 mV) and relative high areal mass density of 850 F g(-1) at areal mass of 3.52 mg/cm(2). It is believed that the good electrochemical behaviors mainly originate from its extremely high specific surface area and underneath core-Co "conductive network". The high specific surface area enables more electroactive sites for efficient Faradaic redox reactions and thus enhances ion and electron diffusion. The underneath core-Co "conductive network" enables an ultrafast electron transport.
authors.affiliation: Key Laboratory of Magnetism and Magnetic Materials of Ministry of Education, Lanzhou University, Lanzhou, 730000, Gansu, P. R. China.
authors.forename: Junli
authors.initials: J
authors.lastname: Zhang
authors.forename: Jiecai
authors.initials: J
authors.lastname: Fu
authors.forename: Junwei
authors.initials: J
authors.lastname: Zhang
authors.forename: Hongbin
authors.initials: H
authors.lastname: Ma
authors.forename: Yongmin
authors.initials: Y
authors.lastname: He
authors.forename: Fashen
authors.initials: F
authors.lastname: Li
authors.forename: Erqing
authors.initials: E
authors.lastname: Xie
authors.forename: Desheng
authors.initials: D
authors.lastname: Xue
authors.forename: Haoli
authors.initials: H
authors.lastname: Zhang
authors.forename: Yong
authors.initials: Y
authors.lastname: Peng
keywords: 3D nano-network; Co@Co3O4 core-shell structure; conductive network; electrochemical capacitors; surface oxidating