三维石墨烯正极材料在锂离子电池中的应用

Application of Three-dimensional Graphene as a Cathode Material in Lithium Ion Battery

三维氧化石墨烯采用改性的Hummer法制备,经过水热反应和高温氮化获得。利用扫描电镜(scanning electron microscopy,SEM)、X射线衍射(X-ray diffraction,XRD)、拉曼(Raman)的测试方法对三维石墨烯材料进行研究。通过恒流充放电循环和交流阻抗谱等电化学方法对三维石墨烯材料作为电池的正极材料进行研究。结果表明,氮化温度为800℃时,所获得的首次放电比容量为261 mAh/g,高于氮化温度为700℃和900℃的首次放电比容量201 mAh/g和196 mAh/g。在充放电循环次数为50次以后,氮化温度为800℃的三维石墨烯材料的比容量几乎没有衰减,这表明其具有较好的循环稳定性。这些预示着三维石墨烯材料作为正极材料在锂离子电池中具有很大的应用前景。

Three-dimensional graphene oxide is prepared by modified Hummer method and obtained through hydrothermal reaction and high temperature nitridation. The three-dimensional graphene material is studied by using scanning electron microscopy（SEM）, X-ray diffraction（XRD） and Raman spectrum. The three-dimensional graphene material as a cathode material of Li-ion battery is studied by electrochemical methods such as the constant current charge-discharge cycle and AC impedance spectroscopy, etc. The results show that the first specific discharge capacity is 261 mAh/g at a nitridation temperature of 800 ℃, which is higher than 201 mAh/g and 196 mAh/g at 700 ℃ and 900 ℃ respectively. After 50 times of charge-discharge cycles, the specific capacity of three-dimensional graphene material at a nitridation temperature of 800 ℃ has almost no decay, which indicates that it has a better cycle stability. These indicate that the three-dimensional graphene materials as cathode materials in lithium ion batteries have great application prospects.