Effects of Cr content on electrochemical properties of melt-spun Al75-xSi25Crx alloy anodes for lithium-ion batteries
(Key Laboratory for Non-equilibrium Synthesis and Modulation of Condensed Matter of Ministry of Education,
State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China)
State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China)
Abstract: Melt-spun Al75-xSi25Crx (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 Al73Si25Cr2 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 Al71Si25Cr4. 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 Al13Si4Cr4, 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.
Key words: lithium-ion battery; Al-Si-Cr alloy; melt spinning; electrochemical property; lithiation activity