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, thermogravimetric and differential thermal analysis and high resolution electron microscopy, it is found that copper exists at the surface of natural graphite in the forms of metallic copper and copper carbides. Since the deposited copper covers and removes some active sites at the surface of natural graphite, which absorbs water relatively easily, cycling behavior in the presence of 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.