Microstructural Transformation and Electrochemical Properties of Mg-Ni-Y-La Amorphous Alloy

摘要:

采用铜模喷铸法制备了Mg60Ni23.6Y0.5La15.9块体非晶合金，并对其微观组织结构及电化学性能进行了研究。用XRD和SEM对Mg60Ni23.6Y0.5La15.9非晶合金在充放电过程中的微观结构进行分析。采用自动充放电测试系统对Mg60Ni23.6Y0.5La15.9非晶合金电化学性能进行了测试。结果表明：在吸氢放氢过程中合金的非晶态结构逐步转变为晶态，并且随着循环的进行逐渐形成了Mg2NiH4、Mg2Ni和Mg(OH)2相。电化学性能测试结果表明：Mg60Ni23.6Y0.5La15.9非晶合金电极的放电容量变化过程可以分为4个阶段，其最大放电容量达到410.5 mAh/g，从而说明非晶结构有可能是非晶电极达到最大放电容量的关键因素

Abstract:

The bulk amorphous alloy Mg60Ni23.6Y0.5La15.9 was prepared by copper-mold inject casting. Its microstructural transformation and electrochemical properties were investigated. The microstructures of Mg60Ni23.6Y0.5La15.9 amorphous alloy during charge and discharge cycling were characterized by XRD and SEM. The electrochemical performances of the alloy were tested by an automatic charge and discharge apparatus. The results show that the amorphous structure transforms into crystallized one step by step and Mg2NiH4, Mg2Ni and Mg(OH)2 phases are formed gradually during the process of hydrogenation and dehydrogenation. Furthermore, the result of electrochemical characteristics testing shows that the change process of discharge capacity for Mg60Ni23.6Y0.5La15.9 amorphous alloy can be divided into four stages and the highest discharge capacity reaches 410.5 mAh/g. It is found that the amorphous structure may be a critical factor to obtain the maximum discharge capacity.