化学处理对多壁碳纳米管电化学储锂性能的影响

为了提高多壁碳纳米管(MWNTs)的电化学储锂性能,对MWNTs采用如下方法处理:混酸浸泡(H2SO4/HNO3)→高温处理→Li2CO3溶液浸泡,将所得样品和原始样品进行结构及电化学性能测试。结果表明,经处理的MWNTs样品的准石墨层间距增大,表面产生羰基等官能团,电化学储锂容量比原始样品提高约45%～85%。通过微分容量曲线对原始和处理后的样品进行机理分析,可以看出处理过的样品其电化学嵌脱锂的电压峰值之间的差值较未处理的样品小,说明锂离子在该样品中脱出所受到的阻力减小。

Effect of chemical treatment on electrochemical intercalation of lithium ion into MWNTs

In order to improve the electrochemical lithiation performance of multi-walled carbon nanotubes(MWNTs),the chemical treatment was carried out in terms of the following processes: first soaked in acid mixture,then heated in high temperature,at last soaked in solution of Li2CO3.The investigations of structure and electrochemical lithiation of MWNTs and the treated MWNTs were carried out.The electrochemical lithiation capacities of the treated MWNTs were increased by about 45%-85 % compared to the original MWNTs.The reason may be that the distance between the pseudo-graphite layers in MWNTs were enlarged by the insertion and de-insertion of H2SO4 molecular into pseudo-graphite layers so that the resistance of Li intercalated into MWNTs was weakened.The carbonyl group was observed at the treated MWNTs by FT-IR.It is noted that the carbonyl group was much helpful in forming SEI membrane at the surface of MWNTs electrode.