Temperature-dependent synthesis of SnO2 or Sn embedded in hollow porous carbon nanofibers toward customized lithium-ion batteries

Lithium-ion batteries (LIBs) have been widely used as grid-level energy storage systems to power electric vehicles, hybrid electric vehicles, and portable electronic devices. However, it is a big challenge to develop high-capacity electrode materials with large energy storage and ultrafast charging capability simultaneously due to the sluggish charge carrier transport in bulk materials and fragments of active materials. To address this issue, composite electrodes of SnO2 nanodots and Sn nanoclusters embedded in hollow porous carbon nanofibers (denoted as SnO2@HPCNFs and Sn@HPCNFs) were respectively constructed programmatically for customized LIBs. Highly interconnected carbon nanofiber networks served as fast electron transport pathways. Additionally, the hierarchical hollow and porous structure facilitated rapid Li-ion diffusion and alleviated the volume expansion of Sn and SnO2. SnO2@HPCNFs delivered a remarkably high capacity of 899.3 mA h g−1 at 0.1 A g−1 due to enhanced Li adsorption and high ionic diffusivity. Meanwhile, Sn@HPCNFs displayed fast charging capability and superior high rate performance of 238.8 mA h g−1 at 5 A g−1 (∼10 C) due to the synergetic effect of enhanced Li-ion storage in the bulk pores of Sn and improved electronic conductivity. The investigation of the electrochemical behaviors of SnO2 and Sn by tailoring the carbonization temperature provides new insight into constructing high-capacity anode materials for high-performance energy storage devices.