Facile Synthesis of Nanostructured Co3O4 thin Films at Low Temperature for High-Performance Pseudocapacitors

Abstract

Co3O4 as a low cost, environmental friendly and nice corrosion resistant electrode material for pseudocapacitors, owns a high theoretical specific capacitance up to 3650 F g-1. However, the actual specific capacitance of Co3O4 is much lower than its theoretical value according to the present literatures. In order to improve the electrochemical performance of Co3O4 electrodes, various binder-free and self-supported Co3O4 thin films with distinct nanostructures were prepared by facile chemical bath deposition at low temperature (Figure.1). The diverse morphologies of Co3O4 thin films (3D thorn-like structure, porous nanoplates, nanoparticles and ultrathin nanosheets) were controlled by the different anions (SO4 2-, NO3 -, Cl- and CH3COO-) of cobalt sources used in synthesis procedure. Among them, the cobalt acetate derived Co3O4 thin film electrodes (A-Co3O4) exhibit the best electrochemical performances in 2 M KOH electrolyte (Figure. 2), such as a high specific capacitance (1545 F g-1) and nice cycling stability (84.6 % retention after 1000 charge-discharges at a high current density of 4 A g-1). Figure 1