Two non-stoichiometric low-Co AB5 alloys, Ml0.95Mg0.05Ni3.8Co0.3Mn0.3Al0.4 (AB4.8) and Ml0.95Mg0.05Ni3.6Co0.3Mn0.3Al0.4 (AB4.6), were designed to reduce the cost ofAB5 alloys. The maximum discharge capacities of the two low-Co alloys can reach 307 mAh/g forAB4.8 alloy and 298 mAh/g for AB4.6 alloy, respectively. After 300 cycles, the capacity decay is 23% for AB4.8 alloy and 19.1% for AB4.6 alloy. XRD patterns and the microstructure, examined by optic microscope and SEM, show that both of the two low-Co alloys are composed of three phases, LaNi5 matrix phase, AlMnNi2 secondary phase and LaNi tertiary phase. For the two low-Co alloys, the microhardness (HV) of the secondary phase are only half of that of the matrix phase, which could resist the crack propagating and make the alloys not amenable to pulverization. The small amount of Mg promotes to form the soft secondary phase, which is believed to be the reason for improving the cycling stability.

The effect of oxygen on the growth of single-walled carbon nanotubes was studied with Ni–Co alloy powder as catalyst under helium atmosphere of 500 Torr by electric arc discharge. The oxygen included in nickel or (and) cobalt oxides was added in catalyst. The content of oxygen in atmosphere was controlled by changing vacuum degree inside furnace before inputting buffer gas. The examinations of TEM and Raman scattering showed that oxygen in metal oxide as catalyst promotes the nucleation of SWCNT by taking effect on the metal catalyst particles. However, O2 in atmosphere has the role of oxidizing amorphous particles along with nanotubes. When its molar proportion is higher than 0.22 ppm (Parts per million), the carbon nanotubes produced are oxidized and their purity decreases. The diameter of single-walled carbon nanotube obtained under different condition has a narrow distribution around 1.28 nm.

采用温控电弧装置，以Co, Ni 合金粉未作为崔化剂，放电电流为80A，电压为32V，放电时间为5min，研究了不同气氛、压力及温度对制取非晶碳纳米管的影响，确定了优化参数。在环境温度为600°C时，氢气气氛，真空度约为6.6×104 Pa，非晶碳纳米管的产量和纯度质量分数都分别达到了6.5g/h和80%以上，其管径为7~20nm.