锂离子蓄电池硬炭负极材料的初步研究

Study on hard carbon materials as negative eletrodes for Li-ion batteries

用植物纤维做前驱体,制备了不同温度下的热解硬炭材料。通过充放电试验,发现可逆容量可以达到450～500mAh/g,但不可逆容量损失同样也大。探讨了热解温度对制得的硬炭材料的结构及可逆和不可逆容量的影响。通过恒流充放电并结合对材料的结构表征,如X射线衍射、比表面积和孔径分布、电子顺磁共振、扫描电镜和电子能谱分析等,对锂嵌入和脱嵌过程中引起的高的可逆和不可逆容量的原因进行了初步分析。

The hard carbon materials were prepared by pyrolyzing vegetal fiber precursors at various temperatures. The results of charge/discharge tests at constant current show that, high reversible capacities of up to 450-500 mAh/g can be obtained whereas the corresponding irreversible capacity losses are also hihg. The effect of pyrolyzing temperatures on the structures, reversible and irreversible capacities of the asreceived hard carbons was explored. Moreover, the reason for such hihg reversible and irreversible capacities was primarily analyzed based on the results of charge/discharge tests and various structural characterization methods, such as Xray diffraction(XRD), BET specific surface area and poresize distribution, electron paramagnetic resonance(EPR), scanning electron microscopy(SEM) and electron dispersive spectroscopy(EDS), etc.