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

Graphical Better anode by design : A designed anode structure combining the metallic conductivity of 1T-MoS 2 with interconnected TiO 2 /MoO 3 grains is beneficial for fast charge-transfer reactions and reduced transmission losses. Moreover, a flexible carbon framework buffers swollen lithium compounds, such as Li x MoO 3 and Li x MoS 2 , and supports the shrinking delithiated products, with potential for achieving high capacity stability in both Li- and Na-ion batteries. Integrating layered nanostructured MoS 2 with a structurally stable TiO 2 backbone to construct reciprocal MoS 2 /TiO 2 -based nanocomposites is an effective strategy. C@TiO 2 /MoO 3 composite nanofibers doped with 1T-phase MoS 2 nanograins were fabricated by partially sulfurizing MoO x /TiO 2 precursors. By controlling a suitable preoxidation temperature before severe thermolysis of polyvinylpyrrolidone (PVP), the MoO x /TiO 2 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 MoS 2 from the MoO x precursor with preoxidation at 200 °C. After carbonization, the TiO 2 /MoO 3 /MoS 2 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.