Impedance Measurements of PX-Series AMTEC Cells 1999-01-2706
Initial impedance measurements of multi-BASE tube AMTEC cells have been accomplished. These measurements were based on theoretical analyses performed by the Jet Propulsion Laboratory. Electrochemical parameters were derived from a plot of the apparent charge transfer resistance, Ract, as a function of the electrical potential across the beta’’ alumina solid electrolyte. These included the morphology factor, G, the exchange current Joo, and α, the transfer coefficient. The factor G was given a value of 50 as a result of the inability of present equipment to achieve 1.6 volts across a single electrolyte element. Average values for the temperature independent charge exchange factor, B, are also reported. These results were taken from cells with as few as 3300 hours to as many as 12,000 hours of operation. The results show that if the assumed value for G is close to actual values, then Joo and α are much lower than those reported in previous literature, resulting in an increase in the charge transfer resistance.
