Cr含量对熔体快淬Al75-xSi25Crx锂离子电池合金负极电化学性能的影响

摘要

研究熔体快淬Al75_xSi25Crx(x=2,4,7,10,摩尔分数,％)锂离子电池合金负极材料的电化学性能.快淬带由纳米晶和非晶组成.电化学测试表明:负极材料存在活化过程；Al73Si25Cr2负极材料的最大比容量为1119mA·h/g,循环30次后可保持为586 mA·h/g:Al71Si25Cr4合金的循环性能更加稳定,经过30次循环后,容量仅衰减24％；嵌Li极片中未检测到含Li的金属间化合物；退火后,由于惰性相Al13Si4Cr4的形成,合金的比容量减小,嵌Li极片中出现A1Li相;固溶于非平衡态合金中的Cr降低了嵌Li活性,增强了结构稳定性,这是活化和抑制结构演变的主要原因.%Melt-spun Al75-Si25Crx (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 1 119 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 Al71Si2sCr4.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.