The electrochemical properties of melt-spun Al-Si-Cu alloys

Melt spinning was used to prepare Al_75-XSi₂₅Cu _X (X = 1, 4, 7, 10 mol%) alloy anode materials for lithium-ion batteries. A metastable supersaturated solid solution of Si and Cu in fcc-Al, α-Si and Al₂Cu co-existed in the alloys. Nano-scaled α-Al grains, as the matrix, formed in the as-quenched ribbons. The Al ₇₄Si₂₅Cu₁ and Al₇₁Si ₂₅Cu₄ anodes exhibited initial discharge specific capacities of 1539 mAh g^-1, 1324 mAh g^-1 and reversible capacities above 472 mAh g^-1, 508 mAh g^-1 at the 20th cycle, respectively. The specific capacities reduced as the increase of the Cu content. AlLi intermetallic compound was detected in the lithiated alloys. It is concluded that the lithiation mechanism of the Al-Si-based alloys can be affected by the third component. The structural evolution and volume variation can be mitigated due to the formation of non-equilibrium state and the co-existence of nano-scaled α-Al, α-Si, and Al₂Cu for the present alloys.