【摘要】 以微米Al粉和Fe粉为原料,采用直流电弧等离子体气相蒸发法,在氢氩和不同CH₄含量气氛下制备了Al-Fe和Al-Fe-C纳米复合粒子。研究纳米粉体的形成机制、结构、形貌及其电化学性能,着重研究C原子的加入对纳米粒子产物的成分组成、相结构及电化学性能的影响,对各种纳米粒子形成规律及嵌/脱锂电化学机制进行了探讨。结果表明:无碳气氛下制备的Al-Fe粒子呈球状;在含碳气氛下,随着C含量的提高,粒子形貌向柱状和线状发展,粉体相组成由Al向Al₄C₃转变,合金种类由FeAl₂向Fe₂Al₅转变。当电流密度为100 mA/g时,4种复合材料电极的首次放电容量分别为348.8、193.3、275.5和628.8 mA·h/g,金属间化合物Fe₂Al₅相的形成有利于提高充/放电容量和抑制体积变化,有效提高了电极的循环稳定性能。更多还原

【Abstract】 Al-Fe and Al-Fe-C nanocomposite particles were prepared through DC arc-discharge method under a methane atmosphere with micro-sized aluminium and iron powders as the raw materials. The formation mechanism, structures, morphologies and electrochemical performances of the nanoparticles’ samples were studied. The effects of carbon atoms on the composition, phase structure and electrochemical properties were studied, and the formation mechanism of nanoparticles as well as electrochemical intercalation/deintercalation of lithium ions were also discussed. The results indicate that the Al-Fe particles prepared in a carbon-free atmosphere are spherical in shapes, meanwhile, the carbon-containing atmosphere causes the morphology of particles columnar or linear, the composition changes fromAl to Al₄C₃ and from FeAl₂ to Fe₂Al₅ in Al-Fe-C nanocomposite particles. The first discharge capacities of four kinds of nanoparticles’ electrodes are 348.8, 193.3, 275.5 and 628.8 mA·h/g, under the current density of 100 mA/g, respectively. The presence of intermetallic Fe₂Al₅ in the powders favors to improve the capacities and restrain the volume changes during the intercalation/deintercalation of lithium ions, thus the cycle stability of electrode was greatly enhanced.更多还原