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

Abstract

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 MoO_x /TiO₂ precursors. By controlling a suitable preoxidation temperature before severe thermolysis of polyvinylpyrrolidone (PVP), the MoO_x /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 MoO_x 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.

Keywords: batteries; electrochemistry; lithium; nanostructures; sodium.