Self-templating fabrication of Ti-doped SnO2 @carbon nanotubes via electrospinning for high-performance lithium-ion batteries

Abstract

Tin dioxide (SnO2) has attracted extensive attention as an anode for lithium-ion batteries (LIBs) due to its high theoretical specific capacity, however, it suffers from the severe volume changes upon lithiation/delithiation cycling, thus leading to fast capacity fading. To overcome the drawbacks, we herein report a facile one-pot self-templating fabrication of Ti-doped SnO2 @carbon nanotubes (Ti-SnO2 @CNTs), via annealing the electrospun precursor nanofibers of tetrabutyl titanate (TBT), tetraethyl orthosilicate (TEOS), polyvinylidene difluoride (PVDF), polyvinylpyrrolidone (PVP), and stannous chloride (SnCl2). Interestingly, the introduction of TBT or not can lead to the controlled fabrication of the tubular or solid fibrous structure. During the annealing process, the chemical reaction between PVDF, TEOS, and TBT in-situ leads to the formation of tubular structure, while the SnCl2 converts into ultrafine SnO2 nanoparticles, embedding into the PVP-derived N-doped carbon nanotubes. When employed as anode materials for LIBs, the Ti-SnO2 @CNTs deliver high reversible capacities of 868.6/495.9 mAh g−1 at 0.2/1.0 A g−1 after 200/500 cycles, higher than those for the fibrous SnO2 @CNFs counterpart (654.9/391.08 mAh g−1). The better lithium storage performance is related to the unique carbon nanotube structure and the Ti-doping, which bring improved electrical conductivity, enhanced structural stability, and shortened ion diffusion path. More importantly, we demonstrate the facile electrospinning fabrication of tubular nanostructured hybrid electrodes for high-performance energy storage applications.