Synthesis of LSM–YSZ–GDC dual composite SOFC cathodes for high-performance power-generation systems

Abstract

This article investigates a method in further improvement of a (La 0.8 ,Sr 0.2 )MnO 3 (LSM)-Yttria-stabilized zirconia (YSZ) dual composite cathode by adding material with high ionic conductivity such as gadoliniadoped ceria (GDC). A nano-porous composite cathode containing LSM, YSZ, and GDC was prepared by a twostep polymerizable complex (PC) method which minimizes the formation of YSZ-GDC solid solution. The structure of the resulting LSM/GDC-YSZ dual composite cathode was such that the LSM and GDC phases were present on the YSZ core particles without formation of the La 2 Zr 2 O 7 , SrZrO 3 , and GDC-YSZ solid solution. At 800°C, the electrode polarization resistance of the LSM/GDC-YSZ dual composite cathode decreased to 0.266 X cm 2 , compared with 0.385 X cm 2 for the LSM/YSZ-YSZ dual composite cathode. In addition, the Ni-YSZ anode-supported single cell using a LSM/GDC-YSZ dual composite cathode with H 2 as the fuel achieved a maximum power density of 0.65 W cm -2 at 800°C.

Synthesis and evaluation of (La0.6Sr0.4)(Co0.2Fe0.8)O3 (LSCF)–Y0.08Zr0.92O1.96 (YSZ)–Gd0.1Ce0.9O2−δ (GDC) dual composite SOFC cathodes for high performance and durability

“…2, only the primary phases including the LSCF perovskite, YSZ cubic, and GDC cubic phases were detected without formation of YSZeGDC solid solution, La 2 Zr 2 O 7 , and SrZrO 3 . This demonstrates that the two-step PC method prevents the formation of secondary phases, as confirmed in previous results [7]. Fig.…”

“…The maximum power densities were 0.5 W/cm 2 and 1.24 W/cm 2 at 650 C and 800 C, respectively, in reactive gases of hydrogen (250 cc/min) and air (500 cc/min). This represents a huge improvement of the fuel cell performance since the LSM/GDCeYSZ dual composite cathode was developed (maximum power density of 0.65 W/cm 2 at 800 C) [7]. Furthermore, a durability test was performed under a static load of 1.0 A/cm 2 at 800 C, as shown in Fig.…”

“…Most SOFCs are still operated at temperatures of 800 C or above to avoid large polarization losses, thermal mismatch, and interfacial diffusion [1e6]. To reduce the large polarization losses, LSM/ GDCeYSZ dual composite cathodes have been introduced where the LSM and GDC nano-particles are both coated on the YSZ core particles which results in greater performance and durability, demonstrated in our previous research [5,7]. The main purpose of introducing dual composite cathodes is to create an ideal cathode microstructure which improves phase contiguity and interfacial coherence [5].…”

“…Fig. 1 shows the synthetic procedure of the LSCFeYSZeGDC dual composite powder using a two-step polymerizable complex method [7]. Stoichiometric amounts of LaN 3 O 9 6H 2 O (Aldrich, 99.99%), SrN 2 O 6 (Aldrich, 99þ%), Co(NO 3 ) 2 6H 2 O (Aldrich, 98þ%), and FeN 3 O 9 6H 2 O (Aldrich, 98%) along with citric acid (Junsei Chemical Co., 99.5%) were dissolved in deionized water and subsequently, ethylene glycol (Ducksan Pure Chemical, 99.5%) and GDC (Rhodia) core particles were added.…”

Corn-cob like nanofibres as cathode catalysts for an effective microstructure design in solid oxide fuel cells

“…As the cathode reaction only take place at the three-phase boundary (TPB) sites where LSM-YSZ-gas phase meeting together, the microstructure design is an important process to increase the TPB sites from larger active sites and better connectivity for optimizing the cathode electrochemical reaction. [13][14][15] Many efforts have been made to optimize the microstructure of the cathode in order to gain an satisfied polarization resistance by changing various mixed ion/electron conductors, [16][17] production methods (infiltration, impregnation), [18][19][20] preparation conditions (temperature, time , etc), 21 and material morphology (particle size and shape).…”