锂离子电池用高容量负极材料普遍存在首次不可逆容量高、循环性能差等问题. 本文采用高温固相法制备了硅铝/碳锂离子电池负极材料, 制备出的复合负极材料的比容量远高于目前锂离子电池普遍使用的中间相碳微球, 循环寿命则优于同粒度的硅单体为活性中心的硅碳复合材料. Al引入Si/C复合材料中, 有效抑制了材料的首次嵌锂深度,且减缓了电压滞后现象. 制备的复合负极材料首次可逆容量达到600mAh/g, 首次充放电效率在85\%以上, 25次循环后容量仍保持90%以上.
High capacity anode material SiAl/C composite was prepared by thermal annealing process. Its structure was characterized by XRD and its cyclability and potentiostatic
cycling performance were investigated. The charging and discharging test shows SiAl/C composite possesses higher capacity than carbonaceous
mesophase spherules. And its first irreversible capacity is decreased, comparing with Si/C composite prepared under the same conditions.
It is demonstrated that by adding Al into Si/C composite system, its first Li+ insertion depth is suppressed and voltage hysteresis is alleviated.
Obtained SiAl/C composite anode material has a capacity about 600mAh/g for its first Li+ insertion and its coulombic efficiency for the first cycle
is up to 85%. And after 25 cycles, its capacity retention can be retained about 90%.
参考文献
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