アイテム詳細

要旨

Antimony and tin are promising anode materials for sodium-ion batteries due to their high theoretical sodium storage capacities. However, significant volume change during cycling limits their long-term stability and rate performance. Composite engineering can minimize this problem. A versatile method for the synthesis of Sb nanoparticles inside the mesopores of carbon fibers prepared through electrospinning and subsequent carbothermal reduction is presented in this work. The mesopore architecture can host up to 61 wt% of Sb nanoparticles and buffer the volume changes during cycling. Smaller pores in the carbon provide the pathways for reversible insertion/extraction of sodium. This binder-free material provides high rate capability and a long-term cycling performance when used as an anode in half-cells. When cycled at 0.5 A g^-1, the composite shows an initial capacity of 520 mA h g^-1 with 507 mA h g^-1 remaining after 500 cycles. Even at a high current density of 20 A g^-1, a capacity of 197 mA h g^-1 is still achieved. Sn nanoparticles can be embedded in the mesopores of the carbon fibers by a similar method. These Sn-based anodes also show remarkable electrochemical performance, indicating that this approach represents a generally applicable strategy for synthesizing advanced battery anodes.