(青岛大学 杂化材料研究院 材料科学与工程学院，青岛 266071)
摘 要: 采用熔体快淬法制备Mg65Ni27La8非晶电极合金带，采用氧化还原法成功制备石墨烯/纳米银复合膜(G/A)，通过高能球磨将G/A膜成功引入电极合金进行表面包覆改性。通守X射线衍射仪、场发射扫描电镜、激光拉曼光谱仪和高分辨电镜表征显示：还原后的石墨烯呈卷曲的大片层结构，尺寸在2~5 μm之间，银纳米颗粒均匀地分散在石墨烯片层上，尺寸在10~20 nm之间。用恒流充放电的方法在三电极电池测试仪上测定其电化学循环性能，实验结果表明改性后合金表面的氧含量由21%降低为包覆后的10%，G/A膜有效阻止合金表面的腐蚀和粉化开裂，包覆改性后电极合金的极限电流密度提高了2.54倍，电极的接触阻抗降低87.2%，电极合金的最高放电容量由610.8 mA？h/g上升为814.8 mA？h/g，经过20个循环后的放电容量保持率由79.86%提升为85.76%，显著提高其电化学性能。
关键字: Mg-Ni-La系贮氢合金；石墨烯；微观结构；电化学性能；表面改性
（Institute of Hybrid Materials, College of Materials Science and Engineering, Qingdao University, Qingdao 266071, China）
Abstract:A new graphene/Ag (G/A) nanocomposite additive was prepared successfully through oxidation/ reduction method. Mg65Ni27La8 amorphous alloy was prepared by melt spinning. The amorphous alloy was successful modified with G/A through high energy ball milling. The G/A was characterized by high-resolution transmission electron microscopy (HRTEM), X-ray diffractometry (XRD), Raman spectrometry and scanning electron microscopy (SEM), respectively. The results show that a coiled structure is present with the size between 2-5 μm for graphene, the silver nanoparticles with the size of 10-20 nm evenly disperse on the graphene sheets. The electrochemical performance determination is executed on the three electrode cell tester. The experimental results show that the oxygen content on the surface of the modified alloy decreases from 21% to 10%, the G/A film can effectively prevent alloy from corrosion and cracking, the limiting current density of modified alloy increases by 2.54 times than that before surface modification, the contact electrode impedance is reduced by 87.2%, the highest discharge capacity of the modified alloy increases from 610.8 to 814.8 mA？h/g, the discharge capacity retention rate of 20 cycles increases from 79.86% to 85.76%, significantly improves its electrochemical performance.
Key words: Mg-Ni-La hydrogen-storage alloy; graphene; microstructure; electrochemical property; surface modification
