Effects of Cr content on electrochemical properties of melt-spun Al _75-xSi ₂₅Cr _x alloy anodes for lithium-ion batteries

Melt-spun Al _75-xSi ₂₅Cr _x (x=2, 4, 7, 10, mole fraction, ) alloys were investigated as anode materials for lithium-ion batteries. The as-quenched ribbons consist of nano-grains and metallic glass. The electrochemical measurements reveal that an activation behavior is exhibited in the anodes. The specific capacity of the Al ₇₃Si ₂₅Cr ₂ anodes can reach a maximum of 1119 mA·h/g and maintain at 586 mA·h/g after 30 cycles. A more stable cycle performance is shown and a capacity loss is only 24 over 30 cycles for Al ₇₁Si ₂₅Cr ₄. The intermetallic compounds with Li cannot be detected in the lithiated anodes. After the ribbons were annealed, the specific capacities become much lower due to the formation of inert Al ₁₃Si ₄Cr ₄, and an AlLi phase can be tested in the lithiated anodes. The Cr dissolved in the non-equilibrium alloys causes low lithiation activity and strong structure stability, which could be the main reason of the activation and a restriction of structure evolution.