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

Melt spinning was used to prepare Al75−XSi25CuX (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 Al74Si25Cu1 and Al71Si25Cu4 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.

► Non-equilibrium Al75−XSi25CuX alloys exhibit high lithiation storages.
► The lithiation mechanism is different from melt-spun Al–Si–Mn system.
► The structural evolution is mitigated in the non-equilibrium alloys.
► Volume variation is alleviated due to the co-existence of Al2Cu, α-Si and α-Al.