.1996 (Restraint of Electrolyte Loss)

1990 (Tile)

1992 (Matrix and Reinfoced Anode)

lata, 923K 150nxA/cm2,11^=40%

5,000 10,000 15,000 Operation Time (hours)

Fig. 1 Progress of single-cell performances


1.1 Restraint of NiO cathode dissolution

To restrain the cathode dissolution, Toshiba has discovered three kinds of effective countermeasures; a LiFe02 layer, an out-of-cell oxidized NiO cathode, and a Li2C03-Na2C03 eutectic electrolyte. Fig.2 shows the Ni amount detected in the electrolyte layers of a conventional cell with in-situ oxidized NiO cathode and ah advanced cell adopting the countermeasures after holding both the cells in 70Air/30C02 at 923K for 50 hours. By taking such countermeasures, the NiO dissolution rate could be reduced to about 1/20. Fig.3 shows the electric generating test results for a single-cell taking the countermeasures. The test was conducted under the accelerating condition of various CO2 partial pressures from 0.3atm to 3.0atm. In the figure, the operation time on the horizontal axis was expanded by the accelerating times of CO2 partial pressures. From the figure, it is estimated that at least 20,000 hours could be expected as the cell life from the NiO cathode dissolution point of view.


In-Situ NiO LiFe02 + Ex-Situ NiO

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