Structural evolution and electrochemical performance of Li ₂MnSiO₄/C nanocomposite as cathode material for li-ion batteries

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 ^-1 at 30°C, while the Li₂MnSiO₄ electrode 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 Li₂MnSiO ₄/C during the delithiation, contributing to a reversible structural change and good cycling performance.