Three-dimensional porous ZnCo(2)O(4) sheet array coated with Ni(OH)(2) for high-performance asymmetric supercapacitor.

Hierarchical ZnCo2O4@Ni(OH)2 sheet composite structures on Ni foam were rationally designed and successfully synthesized. The ZnCo2O4 micro-sheets grown on Ni foam served as the skeleton to improve the electrical conductivity of redox active Ni(OH)2 materials, providing more electroactive sites for the faradaic reaction, and solidify the Ni(OH)2 materials onto Ni foam as a current collector. The electrode of ZnCo2O4@Ni(OH)2 showed an ultrahigh areal capacitance of 4.6F/cm(2) at a current density of 2mA/cm(2). A lightweight and small asymmetric supercapacitor (ASC) device was successfully fabricated using the ZnCo2O4@Ni(OH)2 and carbonized filter paper (CFP) as positive and negative electrode, respectively. The ASC could work in a large potential window of 0-1.8V and achieve a high energy density of 49Wh/kg at 428W/kg.