3D ordered mesoporous TiO2@CMK-3 nanostructure for sodium-ion batteries with long-term and high-rate performance.

Abstract：Sodium ion battery is abundant in resources and costs low, making it very competitive in the large-scale energy storage devices. The anatase TiO2 electrode material with insertion/extraction mechanism shows stable cycling performance，which is more in line with the technical requirements of large-scale energy storage batteries. To improve the electrical conductivity and stability of the TiO2 electrode materials, we have synthesized anatase TiO2 and CMK-3 composite. TiO2 nanoparticles were deposited on the surface of CMK-3 by hydrothermal reaction, and the anode material of the sodium ion batteries with 3D network structure was prepared. With the CMK-3, the structure stability, conductivity and reaction kinetics of TiO2@CMK-3 composite is improved. The electrochemical behavior is dominated by pseudocapacitance, which gives the material excellent high-rate performance. It delivers a reversible specific capacity of 186.3 mA h g-1 after 100 cycles at the current density of 50 mA g-1, 124.5 mA h g-1 after 500 long-term cycles, meanwhile it shows an outstanding rate performance, a reversible specific capacity of 105.9 mA h g-1 at 1600 mA g-1, 177.3 mA h g-1 when the current density drops to 50 mA g-1.