Synthesis of porous Co3O4 nanoflake array and its temperature behavior as pseudo-capacitor electrode

A porous Co3O4 nanoflake array film grown on nickel foam is prepared by a hydrothermal synthesis for pseudo-capacitor application. The pseudocapacitive behavior of the Co3O4 nanoflake array is investigated by cyclic voltammograms (CV), galvanostatic charge-discharge tests and electrochemical impedance spectroscopy (EIS) in 2 M KOH at different temperatures. The specific capacity is 210,289 and 351 F g(-1) at 2 A g(-1) tested at -5 degrees C, 25 degrees C and 60 degrees C, respectively, corresponding to that of 184, 243 and 242 F g(-1) at 20 A g(-1). After 4000 cycles at 2 A g(-1), the remaining specific capacity is 187, 342 and 124 F g(-1) tested at -5 degrees C, 25 degrees C and 60 degrees C. It shows that with increasing the temperature from -5 degrees C to 60 degrees C, the specific capacity increases, while the cycling stability becomes worse. The operation temperature has a pronounced influence on the pseudocapacitive performance of Co3O4 nanoflake array. (C) 2014 Elsevier B.V. All rights reserved.