(青島大學(xué) 雜化材料研究院 材料科學(xué)與工程學(xué)院，青島 266071)
摘 要: 采用熔體快淬法制備Mg65Ni27La8非晶電極合金帶，采用氧化還原法成功制備石墨烯/納米銀復(fù)合膜(G/A)，通過高能球磨將G/A膜成功引入電極合金進行表面包覆改性。通守X射線衍射儀、場發(fā)射掃描電鏡、激光拉曼光譜儀和高分辨電鏡表征顯示：還原后的石墨烯呈卷曲的大片層結(jié)構(gòu)，尺寸在2~5 μm之間，銀納米顆粒均勻地分散在石墨烯片層上，尺寸在10~20 nm之間。用恒流充放電的方法在三電極電池測試儀上測定其電化學(xué)循環(huán)性能，實驗結(jié)果表明改性后合金表面的氧含量由21%降低為包覆后的10%，G/A膜有效阻止合金表面的腐蝕和粉化開裂，包覆改性后電極合金的極限電流密度提高了2.54倍，電極的接觸阻抗降低87.2%，電極合金的最高放電容量由610.8 mA？h/g上升為814.8 mA？h/g，經(jīng)過20個循環(huán)后的放電容量保持率由79.86%提升為85.76%，顯著提高其電化學(xué)性能。
關(guān)鍵字: Mg-Ni-La系貯氫合金；石墨烯；微觀結(jié)構(gòu)；電化學(xué)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
