球磨对Mg_(1.8)Al_(0.2)Ni_(0.8)Mn_(0.2)合金性能影响的研究

Study on the effect of the ball milling on the performance of the Mg_(1.8)Al_(0.2)Ni_(0.8)Mn_(0.2) alloy

分别采用固相扩散法和随后球磨两步法制备Mg1.8A l0.2N i0.8Mn0.2型贮氢合金,研究了球磨对合金相的形成和其电化学性能的影响。SEM测试显示,球磨过程有利于非晶相的形成。充放电测试表明,在100 mA/g放电电流条件下,经过球磨后的合金最高放电容量可达110 mAh/g左右,而单纯固相扩散法合成的合金放电容量约为80mAh/g。循环寿命测试,球磨的样品经过50次循环其容量衰减到40%,非球磨样品经25次的循环即衰减到同样程度。合金的电化学性能的改善与球磨中结构变化所产生的晶体缺陷有关。

Mg1.8Al0.2Ni0.8Mn0.2 hydrogen storage alloy were respectively prepared by solid-state diffusion method and the two-stages method, which includes solid-state diffusion and subsequent ball milling. The effect of the ball milling on the performance of the storage alloy was researched. The SEM demonstrated that the ball milling process gave benefit to the formation of amorphous phase. Charge-discharge tests showed that the maximum discharge capacity of ahoy prepared by bah milling was 110 mAh/g at the current density of 100 mA/g, and the ahoy prepared by solid-state diffusion method just 80 mAh/g. Cycling life tests investigated that the capacity of ahoy prepared by ball milling decreased to 40% after 50 cycles, while the solid-state diffusion method just 25 cycles. The improvement of electrochemical behaviors were ascribed to the crystal defect caused by the microstructure changes during the ball milling process.