Surface Modification of Yttria-Stabilized Zirconia Electrolyte by Atomic Layer Deposition

Abstract

Yttria-stabilized zirconia (YSZ) electrolyte membranes were surface modified by adding a 1 nm thin, high-yttria concentration YSZ film with the help of atomic layer deposition. The addition of the 1 nm film led to an increase of the maximum power density of a low-temperature solid oxide fuel cell (LT-SOFC) by a factor of 1.50 at 400 degrees C. The enhanced performance can be attributed to an increased oxide ion incorporation rate on the surface of the modified electrolyte.

Effects of surface chemistry and microstructure of electrolyte on oxygen reduction kinetics of solid oxide fuel cells

“…However, whether the GB density was the only change made by the thermal annealing remains as an open question. The thermal annealing may induce changes in surface chemistry, which significantly impact ORR kinetics at the electrolyte surface [4,12]. To address how surface chemistry can change upon the thermal annealing at different temperatures, we designed experiments using AR-XPS to probe the chemical composition of the surface and the bulk in a nondestructive way [17,18].…”

“…First, the properties of surface, the interface between the material and the atmosphere, are often the determining factor for the overall device performance, especially in the thin film devices. For example, Chao et al showed that the 1 nm thick YSZ surface modification layer, in which the concentration of oxide ion vacancies was controlled to be higher than that of bulk YSZ, significantly enhanced the surface exchange coefficient [4]. Second, the grain boundary (GB; i.e.…”

Micro solid oxide fuel cells: a new generation of micro-power sources for portable applications

“…sub μm thickness), the operating temperature could be significantly reduced 6,22 . Great efforts have been put in the last decades on the deposition of thin electrolyte layers 20 and several approaches have been pursued, including spray pyrolysis [23][24][25] , sputtering 26,27 , Pulsed Laser Deposition (PLD) 6,19,[28][29][30][31] , Chemical Vapour Deposition (CVD) 32,33 or Atomic Layer Deposition (ALD) 10,34,35 . In particular, physical vapour deposition techniques, mainly PLD, ALD and sputtering, have been proven to be very effective on the deposition of dense and homogeneous layers of such complex oxide films, see e.g.…”

Atomic layer deposition for electrochemical energy generation and storage systems

“…%) by ALD, which led to a 50% increase in power density. 88 Moreover, Fan et al observed that fuel cell performance was improved by modifying the bulk YSZ electrolytes with a thin Y 2 O 3 doped CeO 2 ALD film. 89 These enhancement effects were ascribed to improved oxygen reduction and exchange properties of the ultrathin ALD layer compared with the underlying electrolytes.…”

“…89 These enhancement effects were ascribed to improved oxygen reduction and exchange properties of the ultrathin ALD layer compared with the underlying electrolytes. 88,89 This interfacial modification is expected to improve other SOFCs and even other types of fuel cells. The capability of ALD for coating 3 D complex morphology has also been explored for a high surface area thin film SOFC for further efficiency improvements, as shown by the example in Fig.…”