Sodium-ion batteries (SIBs) are a cost-effective alternative to the commonly used lithium-ion batteries. Tin oxide (SnO₂) is a promising material for use in battery anodes. However, the sluggish reaction kinetics, unstable Sn/Na₂O interface, and large volume expansion of this material are obstacles to practical applications of SnO₂‐based electrodes for SIBs.

Peixin Zhang, Shenzhen University, China, Zhiqun Lin, Georgia Institute of Technology, Atlanta, USA, and colleagues have developed a material in which SnO_2–x nanoparticles, which have oxygen vacancies, are encapsulated by conductive carbon nanofibers. The resulting composite functions as an anode material with good reaction kinetics.

This is due to the material’s well-defined void spaces and the high discharge capacity of SnO_2–x nanoparticles. The conductive carbon matrix allows a rapid electron/ion transfer and hinders SnO_2–x volume expansion during the charge/discharge process, which gives the material excellent cycling stability. In addition, the composite does not require binders or conductive additives to operate as a working electrode.

The team believes that their strategy could be extended to other metal-oxide-containing carbon composites for use as electrodes in high-performance energy-storage systems.

• Robust SnO_2–x Nanoparticle-Impregnated Carbon Nanofibers with Outstanding Electrochemical Performance for Advanced Sodium-Ion Batteries,
  Dingtao Ma, Yongliang Li, Hongwei Mi, Shan Luo, Peixin Zhang, Zhiqun Lin, Jianqing Li, Han Zhang,
  Angew. Chem. Int. Ed. 2018.
  https://doi.org/10.1002/anie.201802672