Co3O4 coated Al composites as anode materials for lithium ion batteries

The Co3O4 coated Al composites with different Co3O4 content were synthesized by a rheological phase reaction in combination with a following heat-treatment process. The composites were characterized by X-ray powder diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, galvanostatic cycling and ac impedance spectroscopy. Results revealed that Al matrix is coated by Co3O4 nanoparticles to form a core-shell structure. The composites exhibit improved cycle performance than pure Al particles. After ten cycles, the capacity retentions of Al-1 wt.% Co3O4, Al-3 wt.% Co3O4 and Al-5 wt.% Co3O4 are 66.8, 69.9 and 70.1% respectively, which are much higher than that of pure aluminum (42%). The improvement of cycle performance is related to the formation of core-shell structure, which plays important roles in the enhancement of mechanical stability and the reinforcement of electronic contact.