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Metal–Organic Framework Templated 3D Hierarchical ZnCo 2 O 4 @Ni(OH) 2 Core–Shell Nanosheet Arrays for High‐Performance Supercapacitors
Author(s) -
Han Xue,
Yang Yujing,
Zhou JiaoJiao,
Ma Qingxiang,
Tao Kai,
Han Lei
Publication year - 2018
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201804327
Subject(s) - nanosheet , materials science , supercapacitor , electrode , chemical engineering , faraday efficiency , capacitance , nanotechnology , porosity , electrochemistry , composite material , chemistry , engineering
Designing core–shell electrode materials with desired components and architectures is a promising strategy for boosting electrochemical performance. Here, three‐dimensional hierarchical ZnCo 2 O 4 @Ni(OH) 2 core–shell nanosheet arrays have been successfully fabricated on a Ni foam substrate, in which the porous ZnCo 2 O 4 nanosheet “core” as the conductive scaffold was synthesized by a metal–organic framework (MOF)‐templated method, and the ultrathin Ni(OH) 2 nanoflakes “shell” with rich active sites were grafted on the ZnCo 2 O 4 nanosheet through a hydrothermal treatment. When directly used as a free‐standing electrode for supercapacitor, these hierarchical ZnCo 2 O 4 @Ni(OH) 2 core–shell nanosheet arrays exhibited a high capacitance of 3063.2 mF cm −2 (1021.1 F g −1 ) at the current density of 1 mA cm −2 . This electrode significantly outperformed individual Ni(OH) 2 or ZnCo 2 O 4 nanosheet arrays, benefiting from the robust core–shell arrays on Ni foam with good electrical conductivity and abundant active sites, as well as the synergetic effect between MOF‐derived porous ZnCo 2 O 4 “core” and the ultrathin Ni(OH) 2 “shell”. Moreover, the assembled ZnCo 2 O 4 @Ni(OH) 2 //activated‐carbon asymmetric supercapacitor displayed excellent energy and power densities (maximum of 40.0 Wh kg −1 and 8.02 kW kg −1 ) and superior cycling stability of 98.4 % retention with 91.2 % coulombic efficiency over 5 000 cycles at 10 A g −1 .