Electrolyte and Full Materials Sets

Overview

There has been significant recent advancements in SOFC materials set development for use in reversible applications [1,2,3]

• means of optimizing electrode performance
• expected degradation rates in fuel cell and electrolysis modes
• manufacturing process impacts on reversible SOFC performance.

We use wet-chemical-route fabrication and composition optimization of electrode and electrolyte materials;

We manufacture planar anode-supported SOFC button cells (1” diameter) using tape-casting, screen-printing, and co-firing processes;

We test planar anode-supported button cell (1” diameter) reversible SOFCs;

We are initially focused on LSGM-based electrolyte materials investigation
Strontium- and magnesium-doped lanthanum gallate (LSGM: La₁-_xSr_xGa1_-yMg_yO3- _d^[4,5,6,7] perovskite-type compound one of the most promising candidate SOFC electrolyte materials high oxygen ionic conductivity (0.17 S/cm) at 800°C, which is comparable to that of YSZ at 1000°C excellent stability over a broad range of oxygen partial pressure from 1 to 10^-22 atm

Goals and Objectives

Overall Goal:
Manufacture and test intermediate-temperature reversible SOFCs based on a novel materials set for applications in renewable energy systems.

Objectives:
Address the primary shortcomings and challenges that have plagued recent reversible SOFC technology by:

• Developing a novel set of intermediate-temperature reversible SOFC materials designed for use in dual modes
  
• Manufacturing planar anode-supported 1” button cell reversible SOFCs
  
• Testing planar anode-supported 1” button cell reversible SOFCs for future scale-up projects
  
• Determining the feasibility of product commercialization.
  

Background

Typical electrolyte performance comparison as a function of temperature

Approach

	La 0.8  Sr 0.2 Ga 0.8				La 0.9 Sr 0.1 Ga 0.8
Mg	0.1	0.115	0.15	0.2	0.1	0.115	0.15	0.2
Co	0.1	0.085	0.05	0	0.1	0.085	0.05	0

Schematic of a novel materials set for intermediate temperature
reversible SOFC – Anode supported button cells manufactured
by tape casting, screen printing and co-firing processes

Current phase includes electrolyte and electrode manufacturing/testing

Next phase may include larger cells, interconnect, surface engineering, etc

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Fuel Cell Mode			Electrolyzer Mode
T (oC)	PH2O (atm)	PH2 (atm)	T (oC)	PH2O (atm)	PH2 (atm)
700	0.03	0.97	700	0.03	0.97
	0.10	0.90		0.10	0.90
	0.30	0.70		0.30	0.70
	0.50	0.50		0.50	0.50
800	0.03	0.97	800	0.03	0.97
	0.10	0.90		0.10	0.90
	0.30	0.70		0.30	0.70
	0.50	0.50		0.50	0.50
800	0.03	0.97	700	1	0
	0.03	0.97		0.99	0.01
	0.03	0.97		0.97	0.03
	0.10	0.90		0.90	0.10

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MHI high temperature (1700^oC) sintering furnace and Paragon calcination kiln

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Personnel

Investigators: J. Brouwer, D. R. Mumm, X. Lu, National Fuel Cell Research Center; R. Perez, S. Hamilton, Southern California Edison
Staff: R. L. Hack
Students: Anh Duong, Grace Ya Qin

Sponsors

Edison Materials Technology Center
Southern California Edison
National Fuel Cell Research Center

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[1] D. Kusunoki, Y. Kikuoka, V. Yanagi, Int. J. Hydrogen Energy, 20 (1995) 831-834.
[2] K. Eguchi, T. Hatagishi, H. Arai, Solid State Ionics, 86-88 (1996) 1245-1249.
[3] J. S. Herring, J. O’Brien, C. Stoots, P. Lessing, R. Anderson, INEEL, Hydrogen, Fuel Cells, Infrastructure Technologies, U.S. DOE FY2003 Progress Report.
[4] T. Ishihara, H. Matsuda, Y. Takita, J. Am. Chem. Soc., 116 (1994) 3801.
[5] M. Feng, J. B. Goodenough, Eur. J. Solid State Inorg. Chem., T31 (1994) 663.
[6] P. Huang, A. Petric, J. Electrochem. Soc., 143 (1996) 1644.
[7] K. Huang, R.S. Tichy, J. B. Goodenough, J. Am. Ceram. Soc., 81 (1998) 2565.

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