Solution-processed Cu2-xO-Fe2O3 composites as novel supercapacitor anodic materials

alpha Fe2O3 and binary composite Cu2-xO-alpha Fe2O3 films were deposited onto fluorine-doped tin oxide glass via a spin spray process at 90 degrees C. Composite films of varying composition such as alpha Fe2O3 (FC-0), CuO-alpha Fe2O3 (FC-1) and Cu2O-alpha Fe2O3 (FC-2) were prepared by controlling the ion molar ratio of the precursor source solution. The FC-0 surface exhibited poor wetting traits toward water (theta(c) > 90 degrees). Conversely, the FC-2 surface displayed good wettability, exhibiting a water contact angle <10 degrees. When serving as supercapacitor electrodes, the obtained FC-0, FC-1 and FC-2 electrodes demonstrated a wide negative potential window of -0.9 V to 0 V vs Ag/AgCl in a 0.5 M aqueous Na2SO4 solution. The supercapacitor comprising the FC-2 electrode exhibited an area normalized capacitance of 182.4 mF cm(-2) at 0.5 mA cm(-2), which is similar to 23.4 times greater than the corresponding FC-0 electrode (7.8 mF cm(-2) at 0.5 mA cm(-2)). Furthermore, the FC-2 supercapacitor demonstrated a capacitance retention of 92%, which suggests good long-term cycling stability. This study indicates that the spin-sprayed Cu2-xO-Fe2O3 composites are promising candidates for high performance supercapacitor electrode materials. (C) 2019 Elsevier Ltd. All rights reserved.