Rationally designed CuCo2O4@Ni(OH)2 with 3D hierarchical core-shell structure for flexible energy storage

J Colloid Interface Sci. 2019 Dec 1:557:76-83. doi: 10.1016/j.jcis.2019.09.010. Epub 2019 Sep 4.

Abstract

Composite electrodes that possess both rational structures and appropriate integration are needed to deliver high electrochemical performance in energy storage devices. In this paper, a flexible and binder-free electrode material based on a heterogeneous core-shell structure of CuCo2O4@Ni(OH)2 nanosheets grown on carbon cloth was fabricated by a simple method. The unique three-dimensional hierarchical structure gives the electrode a large specific surface area, which enables rapid response and increases of specific capacitance. The CuCo2O4@Ni(OH)2/carbon fiber cloth (CFC) composite electrode exhibited a specific capacitance of 2160 F g-1 at 1 A g-1 and a good rate capability energy of 82.7% at 20 A g-1. A flexible all-solid-state asymmetric supercapacitor (FAASC) was assembled with the CuCo2O4@Ni(OH)2/CFC electrode as the positive electrode, and activated carbon (AC)/CFC as the negative electrode. This device showed both a high energy density and power density (58.9 W h kg-1 at a power density of 400 W kg-1), and good long-term cycling stability. Furthermore, the assembled CuCo2O4@Ni(OH)2/CFC//AC/CFC devices were capable of driving a blue light-emitting diode after a short charge. The remarkable performance of this CuCo2O4@Ni(OH)2/CFC electrode indicates that this heterogeneous structure has great potential for applications in flexible high-performance energy storage devices.

Keywords: CuCo(2)O(4)@Ni(OH)(2); Flexible device; High specific capacitance; Supercapacitors.