氯化鹽類對質子交換膜燃料電池性能影響之研究

Abstract

本文探討使用含有氯化鹽類之陰極燃料氣體，對質子交換膜燃料池性能影響之研究。利用超音波震盪器將含有氯化鹽類的水溶液震盪成霧氣與陰極氣體混合，改變氯化鹽水溶液的濃度即可改變混和氣體內鹽分的濃度。結果顯示：五小時實驗測試，氯化鈉並不會因為濃度增加而影響電池之性能；另外，電流密度的改變也不會對燃料電池的性能造成影響。而氯化鈣，在低電流密度時，濃度的變化對燃料電池性能影響並不顯著，但當電流密度增加，濃度影響隨之提高，當電流密度越大而濃度越大，對燃料電池的性能影響的越嚴重。 累積操作時間氯化鹽類的燃料電池實驗，在定電流密度1A/cm2，操作108小時後，由線性方程式可計算出氯化鈉實驗衰減率為-1.082 mV h-1；而氯化鈣實驗衰減率為-3.446 mV h-1。另由極化曲線可觀察出，氯化鈣比氯化鈉對燃料電池性能影響較大，其造成性能下降的機制主要因腐蝕產生歐姆阻抗的增加及濃度極化的損失。氯化鹽類會影響直子交換膜內物種的傳輸行為。

This study presents an investigation of the proton exchange membrane fuel cell performances with the presence of chlorides in the cathode gas. Moisturized by the ultrasonic vibrator, the sodium chloride and calcium chloride were fed into the supply oxidant gas at different elevated concentrations. The results of five-hours testing show that the exist of sodium chloride in the cathode gas has no sensible influence on the cell performance for the set operation currents, while in the case of calcium chloride, the decay of output voltage increases with increasing operating current density. The degradation rate of the cell voltage is -1.082 mV h-1 and -3.446 mV h-1 for 108 hours operation of cell with sodium chloride and calcium chloride in the cathode gas respectively at the current density of 1A/cm2. The polarization curves indicate that the mechanisms of the performance decay are mainly due to the ohmic and mass transport overpotentials that arise from the increasing of cell resistance and the hindrance of the passage for the reaction species by the existence of chlorides in the cathode gas.