Microstructure and Properties of the Ni-CGO Composite Anodes Prepared by the Electrostatic-Assisted Ultrasonic Spray Pyrolysis Method

Abstract

Composite NiO–CGO (Ce0.9Gd0.1O1.95) films were deposited on CGO substrates using the electrostatic-assisted ultrasonic spray pyrolysis (EAUSP) method. Deposition parameters were varied systematically to investigate their effects on film microstructure and electrochemical performance. The X-ray diffraction patterns indicate that the desired crystalline phases of NiO and CGO were obtained in the deposited and then the calcined films. The NiO phase was further converted into a crystalline Ni phase after a reduction treatment. Scanning electron microscope examination revealed that the deposition temperature and electric field strength were dominant factors determining the morphology and microstructure of the deposited films. A deposition temperature of 450°C and an electrostatic field introduced by an applied voltage of 12 kV were identified to yield a cauliflower-like structure with high porosity. A film thus deposited with a NiO:CGO mole ratio of 6:4 performed best as a solid oxide fuel cell anode, as revealed by the ac impedance measurement of Ni–CGO//CGO//Ni–CGO cells in an atmosphere of humidified H2. The representative area-specific resistance value was 0.09 Ω·cm2 at 550°C, which was considerably smaller than that obtained by conventional sample preparation routes. In view of the simplicity, efficiency, and economy of film deposition and the sound electrochemical characteristics of the films obtained found in the current work, it is concluded that the EAUSP method is a promising method for the preparation of Ni–CGO composite anode films.