Transformation of 2D Co-LDH into 3D hierarchical hollow Co3O4 polyhedral arrays with enhanced electrochemical performance for supercapacitors

The designed construction of hierarchical porous materials with a large surface area can be potentially used to improve electrochemical properties in supercapacitors. In this study, a facile approach involving the in situ transformation of two dimensional (2D) ultrathin cobalt layered double hydroxide (Co-LDH) into 3D co-based metal organic frameworks (Co-MOFs) on conductive carbon cloth. Carbonizing and oxidizing strategy are subsequently adopted to convert the Co-MOFs precursor into 3D hollow Co3O4 polyhedral arrays. Owing to the 3D hollow architecture of the Co3O4 arrays are uniformly distributed on carbon cloth, which can provide more reaction sites, fast electron transport, and high electrochemical activity. The optimized 3D Co3O4-60@CC as a binder free electrode delivers high specific capacitance of 806 F g(-1) at the current density of 1 A g(-1) as well as excellent cycling stability. In addition, the assembled asymmetric device Co3O4-60@CC//AC achieves high energy density of 25.3 W h kg(-1) at the power density of 752 W kg(-1) and still retains 86.5% of the performance after 4000 cycles. (C) 2020 Elsevier B.V. All rights reserved.