title: Two-step electrodeposition construction of flower-on-sheet hierarchical cobalt hydroxide nano-forest for high-capacitance supercapacitors.
abstract: A novel flower-on-sheet hierarchical morphology of α-Co(OH)2 nanostructures was achieved via an easy two-step synthesis strategy. The method is based on first a galvanostatic electrodeposition (GE) of vertically aligned interconnected Co(OH)2 nanosheets to form a branch layer and second a potentiostatic electrodeposition (PE) of Co(OH)2 microflowers on the obtained branch layer from the secondary growth of their sheet-like precursors. The formation mechanism of this special PE time-dependent nanostructure was proposed and their morphology-dependent supercapacitor properties were also investigated. For a given areas mass loading, high specific capacitances of 1822 F g(-1) have been achieved for the electrode obtained after 200 s GE followed by a 300 s PE in a three-electrode configuration, and it maintained 91% of its initial capacity after 1000 constant-current charge/discharge cycles. Even when the discharge current density was increased from 1 to 50 mA cm(-2), the capacitance was still as high as 1499 F g(-1), indicating an excellent rate performance of the fabricated electrodes. The high performances of the electrodes are attributed to the special porous structure, 3D hierarchical morphology, vertical aligned orientation, and low contact resistance between active material and charge collector.
authors.affiliation: Key Laboratory of Superlight Material and Surface Technology, Ministry of Education, Harbin Engineering University, Harbin, 150001, PR China. zhqw1888@sohu.com.
authors.forename: Wanlu
authors.initials: W
authors.lastname: Yang
authors.forename: Zan
authors.initials: Z
authors.lastname: Gao
authors.forename: Jing
authors.initials: J
authors.lastname: Ma
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Xingming
authors.initials: X
authors.lastname: Zhang
authors.forename: Lianhe
authors.initials: L
authors.lastname: Liu