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

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 Li 0.96 Ti 1.08 S 2 −Li 4 Ti 5 O 12 nanocomposites with tunable compositions and electrical properties are synthesized by the reaction of Li 4 Ti 5 O 12 with CS 2 at elevated temperature. The resulting incorporation of conductive Li 0.96 Ti 1.08 S 2 domain in the Li 4 Ti 5 O 12 matrix is effective in enhancing the electrical conductivity and electrode activity of semiconducting lithium titanate. As anode materials for lithium ion batteries, the obtained Li 0.96 Ti 1.08 S 2 −Li 4 Ti 5 O 12 nanocomposites show much greater discharge capacity and better rate characteristics than does the pristine Li 4 Ti 5 O 12 . The usefulness of the present method is further evidenced from the improvement of the electrochemical activity of semiconducting CsTi 2 NbO 7 after the reaction with CS 2 . The present study clearly demonstrates the in situ formation of conductive metal sulfide domain using CS 2 liquid can provide an efficient and universal way to improve the electrode functionality of semiconducting metal oxide.