High performance MCFC using Li/Na electrolyte

Conference · Tue Aug 01 04:00:00 EDT 1995

OSTI ID:209867

Donado, R A; Ong, E T; Sishtla, C I

The substitution of a lithium/ sodium carbonate (Li/Na) mixture for the lithium/potassium carbonate (Li/K) electrolyte used in MCFCs holds the promise of higher ionic conductivity, higher exchange current density at both electrodes, lower vapor pressure, and lower cathode dissolution rates. However, when the substitution is made in cells optimized for use with the Li/K electrolyte, the promised increase in performance is not realized. As a consequence the literature contains conflicting data with regard to the performance, compositional stability, and chemical reactivity of the Li/Na electrolyte. Experiments conducted at the Institute of Gas Technology (IGT) concluded that the source of the problem is the different wetting characteristics of the two electrolytes. Electrode pore structures optimized for use with Li/K do not work well with Li/Na. Using proprietary methods and materials, IGT was able to optimize a set of electrodes for the Li/Na electrolyte. Experiments conducted in bench-scale cells have confirmed the superior performance of the Li/Na electrolyte compared to the Li/K electrolyte. The Li/Na cells exhibited a 5 to 8 percent improvement in overall performance, a substantial decrease in the rate of cathode dissolution, and a decreased decay rate. The longest running cell has logged over 13,000 hours of operation with a decay rate of less than 2 mV/1000 hours.

• Research Organization: USDOE Morgantown Energy Technology Center, WV (United States)
• OSTI ID: 209867
• Report Number(s): DOE/METC--95/1020; CONF-950886--; ON: DE96000554
• Country of Publication: United States
• Language: English

Related Subjects

30 DIRECT ENERGY CONVERSION
36 MATERIALS SCIENCE
CURRENT DENSITY
DESIGN
DISSOLUTION
ELECTRODES
IONIC CONDUCTIVITY
LITHIUM CARBONATES
MOLTEN CARBONATE FUEL CELLS
SODIUM CARBONATES
STACKS