A 3D porous architecture composed of TiO₂ nanotubes connected with a carbon nanofiber matrix for fast energy storage

To develop high-power and fast energy storage devices, electrode materials with superior ionic and electronic transport properties should be developed. Herein, a novel composite electrode with TiO₂ nanotubes connected onto a conductive carbon nanofiber network is designed and realized through a general route. The carbon matrix is first synthesized using an electrospinning technique and heat-treatment, and the embedded rutile TiO₂ nanoparticles are formed in situ as the starting materials for the hydrothermal reaction. After hydrothermal treatment, a three-dimensional (3D) porous architecture is developed. The mechanistic analysis demonstrates that the raw embedded rutile TiO₂ nanoparticles react with NaOH solution and go out around the carbon nanofiber matrix to form a well-connected 3D porous nanotube/nanofiber architecture. By using the as-prepared films as electrodes for lithium-ion batteries (LIBs) without the application of any additional conductive agent or binder, high initial capacity and excellent rate performance (214 mA h g^-1 at 5 C rate, 180 mA h g^-1 at 10 C rate, 138 mA h g^-1 at 20 C rate and 112 mA h g^-1 at 30 C rate) are achieved. Moreover, the electrode shows stable cycling performance, especially at a high rate of 30 C, without undergoing decay after 1000 cycles.