Composite anode material for lithium ion battery with low sensitivity to water

Here we demonstrate for the first time a novel kind of anode material with low sensitivity to water, which consists of natural graphite and deposited copper. Through measurement of X-ray photoelectron spectroscopy, thermograv imetric and differential thermal analysis and high resolution electron micr oscopy, it is found that copper exists at the surface of natural graphite i n the forms of metallic copper and copper carbides. Since the deposited cop per covers and removes some active sires at the surface of natural graphite , which absorbs water relatively easily, cycling behavior in the presence o f high humidity (1000 ppm H2O) is improved much. Concomitantly, reversible capacity enhances due to alloying of copper with lithium. (C) 2000 Elsevier Science S.A. All rights reserved.