Preparation of nanostructured Ge/GeO2 composite in carbon matrix as an anode material for lithium-ion batteries

Abstract

A Ge/GeO2 composite embedded in a carbon matrix (Ge/GeO2/C) is synthesized using a one-step mechanical ball-milling method, and its potential as a Li-ion battery anode material is evaluated. Characterization using scanning electron microscopy and transmission electron microscopy reveal that the uniformly distributed germanium and oxygen elements are embedded in the carbon matrix. In situ Xray diffraction analysis provides insight into the complex conversion reaction as well as the Li-Ge alloy reaction. The Ge/GeO2/C composite exhibits a fairly high capacity of 915 mAhr, up to 50 cycles (with good cycling and a high rate capability). The improvement in the electrochemical performance arises from the synergistic effects of the reduced particle size, conductive carbon matrix, and catalytic function of Ge to mitigate mechanical strain and provide an efficient network for electron transfer. (C) 2015 Elsevier Ltd. All rights reserved.