The Pre-treatment Of Carbon Nanotubes And Application In Lead Acid Battery And Lithium Ion Battery

This paper first reviews the advances of the additives in the anode, especially the materials based on the carbon for lead acid batteries. It also summarizes preparation processes, structural performances and applications of carbon nanotubes. TEM, SEM, XRD and BET have been used to characterize the carbon nanotubes and and the electrochemical behaviors of the micro powder electrode and cell with MWCNT additive have been estimated by the battery instrument and the electrochemical workstation.High purity multiwalled carbon nanotube (MWNT) bundles were prepared by chemical vapor deposition method. After super-sonic treated in mixed-acid for 4 hours and graphized at 1000℃ for two hours, the MWCNT were added into the positive paste with the amount of 0.2wt%. The BET specific surface area increased from 0.88m²/g to 3.59m²/g and 2.68 m²/g respectively. The cyclic voltammetry curves illustrates that the activity and conductivity of electrodes with MWNTs additives are improved and the impedence of the electrode significantly decreases. The charge/discharge test shows the utilization of positive active material increases from 16.71%, 11.85%; 15.37%, 8.03%; and 14.68%, 12.62% respectively.After ultrasoniced in acid for 4 hours, the MWCNTs were added into the positive paste of lead acid battery with amount of 0.1wt%,0.2wt%,0.4wt%,0.6wt% respectively. After the electrode and cell assembled, the test was carried out. The results show that the addition of MWCNTs improves the property of the cell. The capacity in the first cycle is 46.589mAh/g, 52.87mAh/g, 55.468mAh/g and 57.90mAh/g. However with the increase of MWCNTs addition, the cyclic performance of the cell decreases slightly.Carbon nanotubes filled with single crystalline β-Sn nanowires (β-Sn/CNTs) have been synthesized on the nanosized SnO₂ catalyst by thermal CVD method using C2H2 as carbon source. Lithium ion battery was assembled using the Sn/CNT as anode. The discharge and reversible capacity in the first cycle was 519mAh/g and 344mAh/g respectively. The coulomb efficiency and cyclic performance was also much better than pure Sn. The out layer of cabon nanotube effectively inhibited the decline of capacity of Sn.