Electrospun SnO₂/TiO₂ Composite Nanofibers for Lithium Ion Batteries

Three types of SnO₂/TiO₂ composite nanofibers (homogeneous SnO₂/TiO₂, heterogeneous SnO ₂/TiO₂ and SnO₂ NPs/TiO₂) have been prepared via a facile electrospinning method combined with a sol-gel chemistry, whose electrochemical performance as anode materials in lithium-ion battery was evaluated and compared to that of pure TiO₂ and SnO ₂electrospunnanofibers (NFs). Rutile phase TiO₂nanofibers demonstrated an extremely stable but relatively low gravimetric specific capacity of ∼80 mAh g^-1 when discharged at 100 mA g^-1. In contrast, rutile phase SnO₂nanofibers showed a much more unstable but higher specific capacity, which dropped from initial 800 to ∼35 mAh g^-1 after 50 cycles. The incorporation of structurally unstable SnO₂ into stable TiO₂ matrix can significantly improve both the cycling performance and specific capacity. These composite nanofibers possess a much higher initial gravimetric specific capacity (>500 mAh g ^-1) than rutile phase TiO₂nanofibers and maintain superior capacity retention to pure SnO₂ NFs. The enhanced cycling stability is attributed to the space confinement provided by the structurally stable TiO₂, which finding can provide a beneficial guidance for future lithium ion battery electrode development.