Study on the characteristics of electrochemical storage lithium of carbon nanotubes

Abstract

When carbon nanotubes(CNTs) are used as negative electrode materials of Lithium ion battery, li <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> not only insert in their pipes but also can insert the stitches between pipes, so CNTs can offer a lot of space for li <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">+</sup> encasing. This special microstructure makes the li a little insetting measurement and it is advantage for improving the charge/discharge capacities and current density. Two kinds of CNTs were prepared in this paper, the size and morphology and structure of the CNTs were determined with X-ray diffraction (XRD) and Transmission Electron Microscope (TEM). The charge/discharge characters of CNTs were tested with electrochemical detector and the results showed that there were different between two kinds of CNTs. The CNTs (A) with little d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">002</sub> had higher initial discharge capacity. At first cycle there was 808.9mAh/g discharge capacity, 214.5mAh/g irreversible capacity and 73.4% discharge efficiency. The CNTs (B) with bigger d <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">002</sub> had initial discharge capacity of 1064.1mAh/g, the first irreversible capacity 627.1mAh/g and 41.1% discharge efficiency. Two kinds of CNTs had better recycle character.