Sphere-like MoS2 and porous TiO2 composite film on Ti foil as lithium-ion battery anode synthesized by plasma electrolytic oxidation and magnetron sputtering

In this paper, a sphere-like MoS2 and porous TiO2 composite film was prepared on Ti foil by plasma electrolytic oxidation and magnetron sputtering methods. The prepared film was assembled as a binder-free anode in the lithium-ion battery and a Li foil served as the counter electrode. The specific capacity and cycling stability of the electrode were evaluated, together with the cyclic voltammograms and electrochemical impedance spectra. The TiO2/MoS2 composite film anode combined the advantages of TiO2 with high structural stability and MoS2 with high theoretical capacity. The electrochemical performance exhibited a specific capacity above 400 mAh g−1 at the current density of 100 µA cm−2, which was much higher than that of the TiO2 anode. Besides, after cycling under a high current density of 1000 μA cm−2, the capacity came back to 91% of the initial capacity, showing a good rate capability. The porous TiO2 prepared by plasma electrolytic oxidation can provide a significant number of internal channels for the Li+ diffusion, resulting in a high porosity of 33.5–41.6%, and a high Li+ diffusion coefficient of 3.12 × 10−14–6.67 × 10−14 cm2/s, which was beneficial for the enhanced electrochemical performance.