Structural Evolution and Electrochemical Performance of Li2MnSiO4/C Nanocomposite as Cathode Material for Li-Ion Batteries

摘要

High capacity Li2MnSiO4/C nanocomposite with good rate performance was prepared via a facile sol-gel method using ascorbic acid as carbon source. It had a uniform distribution on particle size of approximately 20 nm and a thin outlayer of carbon. The galvanostatic charge-discharge measurement showed that the Li2MnSiO4/C electrode could deliver an initial discharge capacity of 257.1 mA h g−1(corresponding to 1.56 Li+) at a current density of 10 mA g−1at 30°C, while the Li2MnSiO4electrode possessed a low capacity of 25.6 mA h g−1. Structural amorphization resulting from excessive extraction of Li+during the first charge was the main reason for the drastic capacity fading. Controlling extraction of Li+could inhibit the amorphization of Li2MnSiO4/C during the delithiation, contributing to a reversible structural change and good cycling performance.