68.
A series of experiments have been performed to investigate the effects of electrolyte composition and temperature on the high-rate discharge behaviors of MmNi
5-based AB
5 hydrogen storage alloy electrodes. Two types of AB
5 electrodes have been used using different alloys: Ce-rich alloy V (La
0.26 Ce
0.44Pr
0.1Nd
0.2Ni
3.55Co
0.72Mn
0.43Al
0.3) and La-rich alloy N (La
0.58Ce
0.25Pr
0.06 Nd
0.11Ni
3.66Co
0.74Mn
0.41Al
0.18). Electrolytes EN were obtained by adding a saturated amount of Al
2(SO
4)
3 to the original electrolyte EO (6 M KOH + 1 wt% LiOH). The electrolyte EN has previously been shown to be very effective to stop the self-discharge of the AB
5 electrodes, better charge/discharge cycle life have been observed. The electrochemical properties of the electrodes were measured by two methods: step mode high-rate discharge and continuous mode high-rate discharge. The results indicate that at 298 K and 333 K, high-rate discharge capacity of Ni–MH battery was mostly affected by the chemical composition of the electrolyte, then the type of alloy. Better dischargeabilities in high-rate discharge capacity have been observed in electrolyte EO than in electrolyte EN. The Ce-rich alloy V has a higher high-rate discharge capacity than La-rich alloy N. High-rate discharge capacity decreases in the following order: VEO > NEO > VEN > NEN (VEO denotes the combination of alloy V and electrolyte EO used in the test battery, similarly equivalent representations for NEN, VEO and VEN).
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