Simple synthesis of honeysuckle-like CuCo2O4/CuO composites as a battery type electrode material for high-performance hybrid supercapacitors

Abstract

In this paper, porous CuCo2O4/CuO composites with novel honeysuckle-like shape (CuCo2O4/CuO HCs) have been prepared for the first time by a simple hydrothermal method and followed with an additional annealing process in air. The unique CuCo2O4/CuO HCs consisted of dense and slender petals with length of 1.3–1.5 μm and width of about 50 nm, and possessed a specific surface area of 36.09 m2 g−1 with main pore size distribution at 10.63 nm. When used as the electrode materials for supercapacitors, the CuCo2O4/CuO HCs exhibited excellent electrochemical performances with a high specific capacity of 350.69 C g−1 at 1 A g−1, a rate capability of 78.6% at 10 A g−1, and 96.2% capacity retention after 5000 cycles at a current density of 5 A g−1. In addition, a hybrid supercapacitor (CuCo2O4/CuO HCs//AC HSC) was assembled using the CuCo2O4/CuO HCs as positive electrode and activated carbon (AC) as negative electrode. The HSC device delivered a specific capacity of 187.85 C g−1 at 1 A g−1 and a superior cycling stability with 104.7% capacity retention after 5000 cycles at 5 A g−1, and possessed a high energy density of 41.76 W h kg−1 at a power density of 800.27 W kg−1. These outstanding electrochemical performances manifested the great potential of CuCo2O4/CuO HCs as a promising battery-type electrode material for the next-generation advanced supercapacitors with high-performance.