Co3O4/N-CNT阵列的制备及其锂空气电池性能研究

Preparation and performance of Co3O4/N-CNT arrays for rechargeable Li-air batteries

可充电锂空气电池具有高的理论能量密度,被认为是新型电动汽车领域里最有潜力的能量储存与转换系统。首先对碳纳米管阵列进行氮原子掺杂及表面氧化,形成结构稳定的氮掺杂碳纳米管阵列材料,然后采用热回流法对氮掺杂碳纳米管表面以杂化复合的形式结合纳米Co3O4粒子,形成锂空气电池空气电极。通过扫描电子显微镜、X射线衍射、Raman、XPS等进行表征,结果显示氮掺杂碳纳米管阵列表面上均匀结合纳米Ci3O4颗粒,直径约为50~100 nm左右。以纳米Co3O4/氮掺杂碳纳米管阵列为空气电极,与金属锂片构成锂空气电池,并进行电池充放电性能、循环伏安和交流阻抗等电化学测试,结果表明,在电流密度为0.05 mA/cm^2的条件下循环40次后仍能保持较稳定的循环性能,与纯氮掺杂碳纳米管阵列相比,锂空气电池的充放电性能有了明显的改善。

The rechargeable lithium air battery is considered to be the most potential energy storage and conversion system in the field of new electric vehicles due to its high theoretical energy density.Nitrogen doped carbon nanotube(N-CNT)arrays was firstly prepared and oxidized by chemical vapor deposition method,and then nanoscale Co3O4 particles with diameter of 50-100 nm were hybridized onto the surface of N-CNT arrays by hot reflux method,which could be used as the cathode of Li-air batteries.The prepared Co3O4/N-CNT arrays were characterized by scanning electron microscopy,X-ray diffraction,Raman spectroscopy,and X-ray photoelectron spectroscopy.The electrochemical performance of Li-air batteries made from different Co3O4/N-CNT arrays as the cathode and the lithium metal plate as the anode was characterized by discharge-charge performance,cyclic voltammogram,and impedance spectroscopy tests.The results indicate that at a current density of 0.05 mA/cm2,the prepared Co3O4/N-CNT array hybrid composites achieve relatively stable discharge-charge cycling performance after 40 cycles in Li-air batteries,and can obviously enhance the discharge-charge performances of Li-air batteries compared with the pristine N-CNT arrays.