Synthesis of Titania@Carbon Nanocomposite from Urea-Impregnated Cellulose for Efficient Lithium and Sodium Batteries

Nanostructured TiO2 and TiO2@C nanocomposites were prepared directly from urea‐impregnated cellulose by a simple reaction/diffusion process and evaluated as negative electrode materials for Li and Na batteries. By direct treatment with TiCl4 under anhydrous conditions, the urea impregnation of cellulose impacts both the TiO2 morphology and the carbon left by cellulose after pyrolysis. Hierarchical TiO2 structures with a flower‐like morphology grown from‐and‐at the surface of the cellulose fibers are obtained without any directing agent. The resulting TiO2/cellulose composite is then transformed either into pure TiO2 flowers by calcination in air at 600 °C, or into TiO2@C nanocomposites by pyrolysis under Ar at 600 °C. Electrochemical studies demonstrate that both samples can (de)insert lithium and sodium ions and are promising electrode materials. Electrodes from cellulose: Reactive mineralization has been developed to modify cellulose. Pre‐impregnation of cellulose filter paper with urea affects the morphology of the oxide—a unique superstructure of TiO2 nanoflowers is obtained—and provides doping to carbon left by pyrolytic conversion of cellulose. The resulting electrode material can be used in highly efficient Li and Na batteries.