Ni对高能球磨Mg-Ni合金组织和电化学性能的影响

Effects of Ni Content on Structure and Discharge Capacities of Mg-Ni Alloy Synthesized by High-Energy Ball Milling

摘要:

利用高能球磨工艺制备了不同Ni含量的Mg-Ni合金，采用X射线衍射分析，研究了随Ni含量变化以及球磨时间不同合金组织演变过程，并对其电化学放电容量进行了测试分析。结果表明，随着Ni含量由Mg2Ni，Mg1．5Ni到MgNi的增加，高能球磨Mg—Ni合金体系经历纳米晶Mg2Ni向非晶MgNi过渡并最终形成纳米晶MgNi合金的转变过程。不同组织状态的Mg-Ni合金其电化学容量有较大的差异。随着Ni含量提高，纳米晶MgNi合金增加，在有纳米晶Ni的存在下，Mg-Ni合金的放电容量可高达500mAh／g。延长球磨时间，获得几乎完全纳米晶的MgNi合金组织，由于没有纳米晶Ni的催化作用，导致合金放电容量下降。

Abstract:

The Mg-Ni alloys with different Ni content were prepared by high-energy ball milling. Their structures were determined with X-ray diffraction and their discharge capacities as an electrode were tested. The results show that, as the Ni content increase from Mg2Ni, Mg1.5Ni to MgNi (the ratio of the atom), the structure of Mg-Ni alloy changed from nano-Mg2Ni, amorphous-MgNi to nano-MgNi. The Mg-Ni alloys with different structure exhibit different discharge capacities. As the increase of Ni content, the number of nano-MgNi increase and the discharge capacity could reached 500 mAh/g. As the milling time prolonged, the nano-MgNi with scarcely nano-Ni could be attained. As there was almost no nano-Ni, its discharge capacity is decreased.