C@TiO2 /MoO3 Composite Nanofibers with 1T-Phase MoS2 Nanograin Dopant and Stabilized Interfaces as Anodes for Li- and Na-Ion Batteries.

Integrating layered nanostructured MoS2 with a structurally stable TiO2 backbone to construct reciprocal MoS2 /TiO2 -based nanocomposites is an effective strategy. C@TiO2 /MoO3 composite nanofibers doped with 1T-phase MoS2 nanograins were fabricated by partially sulfurizing MoOx /TiO2 precursors. By controlling a suitable preoxidation temperature before severe thermolysis of polyvinylpyrrolidone (PVP), the MoOx /TiO2 precursors formed a polymer-embedded array through coordination of the Mo source and pyrrolidyl groups of PVP. Sulfidation under water/solvent hydrothermal conditions led to partial formation of metallic 1T-phase MoS2 from the MoOx precursor with preoxidation at 200 °C. After carbonization, the TiO2 /MoO3 /MoS2 nanograins were encapsulated in a carbon backbone in a vertical pattern, providing both chemical contact for confined electron transport and sufficient space to adapt to volume changes. The obtained carbon-based platform not only has the advantages of an integral structure, but also exhibited ultrastable specific capacities of 540 and 251 mAh g-1 for Li-ion batteries and Na-ion batteries, respectively, after 100 cycles.