Effect of fluorinated multi-walled carbon nanotubes as cathode on performance of Li/CF_<i>x</i> batteries

• Main Authors: LI Xu, SUN Xiao-gang, CAI Man-yuan, WANG Jie, CHEN Wei, CHEN Long, QIU Zhi-wen
• Format: Article
• Language: zho
• Published: Journal of Materials Engineering 2019-08-01
• Series: Journal of Materials Engineering
• Subjects: multiwall carbon nanotube; multiwall carbon nanotubes fluoride; lithium/fluoride primary battery
• Online Access: http://jme.biam.ac.cn/CN/Y2019/V47/I8/22

Multiwalled carbon nanotubes(MWCNTs) were fluorinated to get the material of MWCNTs fluoride with different atomic ratio. The ratio of fluorine and carbon was 0.28(CF_0.28), 0.56(CF_0.56) and 0.78(CF_0.78) respectively. The fluoride MWCNTs were used as cathode active material to coat on aluminum foil, lithium metal foil as counter electrode in Li/CF_<i>x</i> batteries. The structures and properties were characterized by thermal gravimetric analyzer(TGA), scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray diffraction(XRD), and X-ray photoelectron spectroscopy(XPS). The electrochemical performance was tested by galvanostatic discharge test. The results show that the battery with CF_0.78 has the best electrochemical performance. At the current density of 39mA/g, the battery displays high discharge specific capacity of 724mAh/g and appears with a more stable platform for the discharge process. At the current discharge rate of 0.05C, the utilization of three kinds of MWCNTs fluoride electrodes is 73.4%, 89.6%, 92.9%. When the discharge rate is 2C, batteries with three different MWCNTs fluoride have discharge specific capacity attenuation rate of 68.8%, 34.1%, and 39.6%. It indicates that the discharge specific capacity attenuation rate can be mitigated to a certain extent with the improved level of fluoridation. Although the discharge capacity attenuation rate of CF_0.78 is higher than that of CF_0.56, CF_0.78 has the most stable discharge curve at the same discharge rate.