Co_(3)O_(4)与膨胀石墨自组装的多面体复合物作为锂离子电池阳极材料

Co_(3)O_(4)and expanded graphite self-assembled polyhedron composites used as anode materials for lithium ion batteries

作为锂离子电池的负极材料,Co_(3)O_(4)因其具有890 mA·h/g的高理论比容量而备受关注。本文通过简单的化学溶液法和热处理制备了Co_(3)O_(4)与膨胀石墨(EG)自组装的多面体复合材料(Co_(3)O_(4)-EG)。当用作锂离子电池的负极材料时,EG与Co_(3)O_(4)质量比为1∶3的Co_(3)O_(4)-EG复合材料电极在0.1 C的电流倍率下经过400次循环后的可逆容量仍高达418 mA·h/g,高于其他Co_(3)O_(4)-EG复合材料(质量比1∶4循环190圈后容量为273 mA·h/g,质量比1∶5循环135圈后的容量为329 mA·h/g),且所有Co_(3)O_(4)-EG复合材料的放电容量均高于纯Co_(3)O_(4)(400圈循环后容量为40 mA·h/g)。Co_(3)O_(4)的纳米结构、EG的优良导电性及自组装后的多面体结构的协同作用使Co_(3)O_(4)-EG复合材料具有优异的储锂性能。

As a cathode material for lithium ion batteries,Co_(3)O_(4)has attracted much attention due to its high theoretical specific capacity of 890 mA·h/g.In this paper,Co_(3)O_(4)and expanded graphite self-assembled polyhedral composites(Co_(3)O_(4)-EG)were prepared by simple chemical solution method and heat treatment.When used as the anode material of lithium ion battery,the reversible capacity of Co_(3)O_(4)-EG composite electrode with the mass ratio of EG to Co_(3)O_(4)of 1∶3 after 400 cycles at the current rate of 0.1 C is still as high as 418 mA·h/g,which is higher than that of other Co_(3)O_(4)-EG composite materials(The capacity is 273 mA·h/g after 190 cycles with a mass ratio of 1∶4 and 329 mA·h/g after 135 cycles with a mass ratio of 1∶5).And the discharge capacity of all Co_(3)O_(4)-EG composites is higher than that of pure Co_(3)O_(4)(The capacity is 40 mA·h/g after 400 cycles).The nanostructure of Co_(3)O_(4),the excellent electrical conductivity of expanded graphite and the synergistic effect of self-assembled polyhedron structure make Co_(3)O_(4)-EG composites have excellent lithium storage properties.