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采用X射线衍射(XRD)分析,充放电测试,线性极化和电位阶跃等方法研究了在750,850,950℃3个不同温度下进行固相烧结对TiNi储氢合金的相结构和电化学性能的影响。结果表明:随着烧结温度的提高,TiNi合金最大放电容量由179.0 mAh.g-1增加到188.1和211.3 mAh.g-1。虽然温度的升高并没有提高合金的交换电流密度,但却大大增强了氢在合金中的扩散速率,扩散系数D从750℃的2.49×10-10cm2.s-1增加到850℃的2.61×10-10cm2.s-1和950℃的3.48×10-10cm2.s-1,从而显著的改善了合金电极的高倍率放电性能(HRD)。950℃烧结后的合金在1500 mA.g-1的放电电流下仍然可以放出84.6 mAh.g-1的电量。
The effects of solid phase sintering at 750, 850 and 950 ℃ on the phase structure and electrochemical performance of TiNi hydrogen storage alloys were investigated by X-ray diffraction (XRD), charge and discharge test, linear polarization and potential step. . The results show that with the increase of sintering temperature, the maximum discharge capacity of TiNi alloy increases from 179.0 mAh.g-1 to 188.1 and 211.3 mAh.g-1. Although the increase of temperature did not increase the exchange current density of the alloy, it greatly enhanced the diffusion rate of hydrogen in the alloy. The diffusion coefficient D increased from 2.49 × 10-10cm2.s-1 at 750 ℃ to 2.61 × 10-10 cm2 · s-1 and 3.48 × 10-10 cm2 · s-1 at 950 ° C., thereby significantly improving the high-rate discharge performance (HRD) of the alloy electrode. The alloy sintered at 950 ℃ can still discharge 84.6 mAh.g-1 at a discharge current of 1500 mA.g-1.