Study On The Al Cu Fe Quasicrystal Modification Of Prepared By Different Methods And Its Lithium Storage Properties

Al-Cu-Fe quasicrystal is a special solid ordered phases with five-time rotational symmetry,a large number of defects in the structure is conducive to the insertion and removal of lithium.The previous research shows that Al-Cu-Fe quasicrystal with similar composition has higher specific capacity than Al-Cu-Fe crystalline alloy,and have very good cycle performance,but the capacity is lower.In this paper,as cast Al₆₄Cu_23.5Fe_12.5 quasicrystal was modified by carbon coating,and the quasicrystal/graphite composites was prepared by mechanical alloying method.In addition,Al₆₄Cu_23.5Fe_12.5 quasicrystal was prepared by mechanical alloying using Al,Cu and Fe element powders as raw materials,the matrix was modified.The lithium storage performance of different materials was analyzed.The main results are as follows:1.The input energy of the high-energy vibration ball milling is too high,and the quasicrystal structure will be destroyed.The input energy of planetary ball milling is uniform and gentle,and it has little effect on the quasicrystal structure of composites materials.High-speed and long-time ball milling can make graphite amorphous.Al-Cu-Fe quasicrystal/graphite composites were obtained by planetary ball milling550 rmp for 80 h.Graphite forms a coating on Al-Cu-Fe quasicrystal,and its structure is similar to onion.It forms a uniform coating on the quasicrystal,increasing defects on the particle surface.The first charge capacity of composites are 480 m Ah/g at a rate of 0.1C,and the capacity basically remained stable.,which is double than estimated theoretical capacity.showing capacity doubling effect and good cycle stability.2.Al-Cu-Fe quasicrystal phase cannot be obtained after high-energy vibration ball milling and subsequent annealing with elemental Al,Cu,and Fe powders as raw materials.Excessive energy input will damage the structure of quasicrystal phases.The pure Al-Cu-Fe quasicrystal phase was obtained by ball milling 250 rpm for 10 h and annealing at 860?for 4 h.The stable capacity of Al₆₄Cu_23.5Fe_12.5 quasicrystal anode is 65 m Ah/g,which is 50%higher than that of as-cast Al-Cu-Fe quasicrystal.