| It is studied that the effect of heat treatment on electrochemical performances of Sichuan mischmetal-type (LPC) hydrogen storage alloys. The microstructures of alloys before and after heat treatment are studied separately. And the optical heat treatment rules which lead to the best electrochemical performances are obtained.The results indicate that: (1) during heating, reversion and recrystallization occur and grains grow, and their feature temperatures are 491℃ and 602℃ respectively; (2) the electrochemical performances of hydrogen storage alloy treated for hours at 400 ℃ improves less than that of the ingots. While the temperature is lower than that of the recrystallization; the maximum discharge capacity is 330mAh/g when charging and discharging at 0.2C; the capacity decay rate at 0.4 C after 400 cycles is 0.13%, and the high rate capability is 84%, which is better than that of ingot; (3) the maximum discharge capacity at 0.2C is 312mAh/g, and that at 1C is 256mAh/g, and the capacity decay rate at 1 C after 220 cycles is about 0.08%, when the alloy is treated for h (4) when the alloy is treated for hours at , themaximum discharge capacity at 0.2C reaches around 340mAh/g, the capacity decay rate at 0.4 C after 400 cycles is 0.10%, and the high rate capability increases to 78%; (5) compared with the maximum discharge capacity loss at 20 ℃, that of all alloys at 40℃ is less than 2%; (6) the maximum discharge capacity of LPC hydrogen storage alloy at 0.2C , the activation rate and the high rate capability are higher; compared with those of Mm hydrogen storage alloy and LPC hydrogen storage alloy containing Ce(15%); (7) the maximum discharge capacity at 0.2C of the alloy treated for hours at reaches 342.8mAh/g; that at 1C is 268mAh/g; and thecapacity decay rate at 1 C after 400 cycles is 011%, which is comparable with that of hydrogen storage alloy made in Japan.
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