Rational design of Co-Ni layered double hydroxides electrodeposited on Co3O4 nanoneedles derived from 2D metal-organic frameworks for high-performance asymmetric supercapacitors

Hierarchical architecture hybrid materials with excellent synergistic effect have been paid close attention for their potential applications in energy storage devices. Herein, we reported an electrode of CoNi layered double hydroxides (LDH) nanosheets electrodeposited on Co3O4 nanoneedles derived from 2D Co-based metal-organic frameworks (Co-MOFs) combined with flexible carbon cloth (CoNi LDH@Co3O4@CC) for asymmetric supercapacitors (ASCs). The Co3O4 nanoneedles served not only as a good pseudocapacitive material but also as an excellent porous skeleton for electrodepositing CoNi LDH nanosheets. The combination of hierarchical core-branch architecture and heterogeneous structure endowed the CoNi LDH@Co3O4@CC electrode with superior electrochemical performance with high specific capacitance (1021.7 F g(-1) at 10 A g(-1)) and good rate capability. Furthermore, the ASC composed of the CoNi LDH@Co3O4@CC as a cathode and N-doped porous carbon nanosheets grown on the carbon cloth (NC@ CC) as an anode achieved a superior energy density of 33.4 W h kg(-1) at a power density of 1600 W kg(-1) and a long cycle life (93.46% after 10,000 cycles at 4 A g(-1)). As a result, this work demonstrated an efficient method for rational design and preparation of the hierarchical core-branch architecture hybrid electrodes for supercapacitors. (C) 2020 Elsevier B.V. All rights reserved.