| In this paper, Al, Al-Sn and Al-Fe nanoparticles were fabricated by a physical vapor condensation method. All the samples were characterized by X-ray diffraction(XRD), high-resolution transmission electron microscopy (HRTEM), and differential scanning calorimeters(DSC). Their lithium storage properties were investigated by galvanostatic cycling.As for Al system, the particle size is about 100nm, and it is coated by amorphous Al2O3 of 1 nm in thickness. Anode slurries prepared were consisted of Al powder, acetylene black and Polyvinylidene Fluoride (PVDF) binder. The effects of current density on the electrochemical properties were investigated. Al electrode in the minimal current density delivers the highest initial discharge capacity (Li intercalation process) of 951.9mAh/g but cycle life is poor. Al electrode in the maximal current density delivers initial discharge capacities of 879.7 mAh/g and possesses relatively good cycleability. After the initial discharge, Al electrode was characterized by XRD and TEM. Only two composites (AlLi and Al2Li3) are found, which corresponds with the initial discharge capacity. After 10 cycles, Al phase was still found in the electrode, which proved that Al is a potential material to replace carbon in Lithium-ion batteries.As for the Al-Sn system, both Al and Sn nanoparticles were observed in XRD results. And the Al proportions in the compressed bulk mixture are different from those of corresponding nanoparticles, which attribute to the difference of the evaporating rate between Al and Sn. The effects of different composition of Al on the electrochemical properties were investigated. Electrode contents 43%Al delivers the highest initial discharge capacity of 640 mAh/g but cycle life is very poor. The electrode contents 93%Al delivers the initial discharge capacity of 375mAh/g and possesses relatively good cycleability.As for the Al-Fe system, only Alo.5Feo.5 is observed in the XRD profiles. The particle size is about 100nm, and it has a shell-core structure. Al-Fe electrode delivers the initial discharge of 38mAh/g, which proves that Al0.5Fe0.5 can react with Li. |
