In Situ Formation of Conductive Metal Sulfide Domain in Metal Oxide Matrix: An Efficient Way to Improve the Electrochemical Activity of Semiconducting Metal Oxide

Abstract

A new effective way to improve the electrochemical activity of semiconducting metal oxide is developed by the in situ formation of conductive metal sulfide domain in the metal oxide matrix. The Li0.96Ti1.08S2-Li4Ti5O12 nanocomposites with tunable compositions and electrical properties are synthesized by the reaction of Li4Ti5O12 with CS2 at elevated temperature. The resulting incorporation of conductive Li0.96Ti1.08S2 domain in the Li4Ti5O12 matrix is effective in enhancing the electrical conductivity and electrode activity of semiconducting lithium titanate. As anode materials for lithium ion batteries, the obtained Li0.96Ti1.08S2-Li4Ti5O12 nanocomposites show much greater discharge capacity and better rate characteristics than does the pristine Li4Ti5O12. The usefulness of the present method is further evidenced from the improvement of the electrochemical activity of semiconducting CsTi2NbO7 after the reaction with CS2. The present study clearly demonstrates the in situ formation of conductive metal sulfide domain using CS2 liquid can provide an efficient and universal way to improve the electrode functionality of semiconducting metal oxide.