磷酸铁锂离子电池正极材料掺碳纳米管的研究

Abstract

应用球磨法于LiFePO4掺杂多壁碳纳米管,制成LiFePO4/MWCNTs复合电极,然后以其组装成锂离子电池.研究不同比例掺杂多壁碳纳米管对复合材料电极电化学性能的影响.XRD、SEM表征及电化学性能测试表明,多壁碳纳米管含量为10%(bymass)的LiFePO4/MWCNTs电极比其它比例的复合电极具有更优良的充放电性能,而且极化小、稳定性强、充放电平台更平稳,导电率更高.在常温0.1C下充放电,首次充、放电比容量分别为139和128.5mAh.g-1,库仑效率达92.4%,循环40次后,电极比容量损失率仅为5.3%.

The LiFePO4/MWCNTs composite was synthesized by ball milling,then the composite electrode was assembled into button lithium-ion batteries.The structure and morphology of the samples,the electrochemical performance of the electrodes were investigated by ways of X-ray diffraction,scanning electron microscopy,cyclic voltammetry and charge-discharge capacity tests. The electrochemical performance of the composite electrodes with different MWNTs contents were studied. The results indicated that the composite electrode containing 10% MWCNTs(by mass)exhibited the most excellent electrochemical performance with the initial charge-discharge capacities of 139 mAh·g-1,128.5 mAh·g-1,respectively,and a Kulun efficiency of 92.4% at 0.1C rate under room temperature.Compared to the electrodes with the different MWCNTs contents,it had the longest and steadiest charge-discharge platform,at the same time,it had the lowest polarization,keeping 94.7% of the initial capacity over 40 cycles.