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_0.96Ti_1.08S₂?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 Li_0.96Ti_1.08S₂ 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 Li_0.96Ti_1.08S₂?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.