Highly active Mo doping TiO 2 as sulfur loaded matrix material for lithium‐sulfur batteries with excellent electrochemical performances

Abstract

Lithium-sulfur batteries have attracted much attention for a long time owing to their high theoretical specific capacity. In this paper, a type of highly active Mo doping TiO2 as sulfur loaded matrix material has been synthesized by a facile solvothermal method. X-ray diffraction and Raman spectrum tests show that Mo atom can enter into the interlayer of TiO2 crystal face and increase the interplanar spacing of titanium dioxide in order to possess a higher electrochemical activity. Small particles morphology and uniform particle size can be evidently observed by scanning electron microscope and after sulfur loading (1:1), it still retains the similar morphology as matrix material. This illustrates that a considerable amount of sulfur has penetrated into the matrix material in order to achieve the ideal sulfur loading effect. When used as electrode active material, it displays the lowest electrochemical and concentration polarization resistance and the specific capacities can reach 1483.08, 1208.57, and 1004.17 mAh g−1 at 0.1, 0.2, and 0.5 C current rates and after 150 cycles, the capacity retention is over 60%. When the sulfur loading mass ratio increases to 1:2 (Mo/TiO2:S), the sulfur composite cathode still maintains considerable lithium-ion diffusion channels and 753.54 mAh g−1 of specific discharge capacity at 0.5 C current rate.