The effects of sintering temperature on the phase structure and electrochemical properties of AB5-5Â mass% LaMg3 composite alloy

In order to investigate the effect of sintering temperature on phase structure and electrochemical properties of AB5-5 mass% LaMg3, as a part of our systematic studies, the AB5-5 mass% LaMg3 composite alloys were prepared by sintering AB5 and LaMg3 powders at 973 K, 1073 K, 1123 K, 1173 K and 1273 K, respectively. Phase structure and electrochemical properties of the composites were investigated. The results show that the composite alloys were composed of matrix AB5 phase and secondary LaNi3 phase. The maximum discharge capacity, high rate dischargeability (HRD) and dischargeability at low temperature increase first and then decrease with increasing sintering temperature. AB5-5 mass% LaMg3 composite alloy sintered at 1123 K has the best overall electrochemical properties. For example, it exhibits as high a discharge capacity as 358 mAh g−1, which is 7.2% higher than that of AB5 alloy, a better HRD and a better dischargeability at low temperature. However, cyclic stability of AB5-5 mass% LaMg3 becomes better with increasing sintering temperature. AB5-5 mass% LaMg3 sintered at 1273 K has the best cyclic stability and its capacity retention after 100 cycles is 94.3%, which is 3.7% higher than that of the commercial AB5 alloy.