Coaxially Integrating TiO₂/MoO₃ into Carbon Nanofibers via Electrospinning towards Enhanced Lithium Ion Storage Performance

Conversion-type transition metal oxide MoO₃ has attracted considerable interest as a promising anode material for lithium ion batteries (LIBs), but it suffers from the low electronic conductivity and the large volume changes upon lithiation/delithiation. To overcome these drawbacks, we herein report the full encapsulation of core-shelled MoO₃-TiO₂ into the carbon nanofibers (CNFs) via a facile coaxial electrospinning followed by a two-step annealing process. TiO₂ shells and MoO₃ cores were coaxially integrated into the porous CNFs (denote the composite as TiO₂/MoO₃@CNFs). The two-step annealing strategy (carbonization in Ar and then oxidization in air) allows the readily encapsulation of MoO₃ into CNFs. When applied as anode materials for LIBs, the coaxial TiO₂/MoO₃@CNFs demonstrate superior lithium storage performance, delivering a high reversible capacity of 561 mAh/g after 300 cycles at 1000 mA/g with a much higher capacity retention of 70.8% than that of the MoO₃@CNFs without TiO₂ layers (only 42.3%). The results clearly demonstrate that the CNFs matrices and the TiO₂ shells together efficiently enhance the electrode conductivity and buffer the volume changes of MoO₃ upon cycling.