Rattle-type porous Sn/C composite fibers with uniformly distributed nanovoids containing metallic Sn nanoparticles for high-performance anode materials in lithium-ion batteries.

Rattle-type porous Sn/carbon (Sn/C) composite fibers with uniformly distributed nanovoids containing metallic Sn nanoparticles in void space surrounded by C walls (denoted as RT-Sn@C porous fiber) were prepared by electrospinning and subsequent facile heat-treatment. Highly concentrated polystyrene nanobeads used as a sacrificial template played a key role in the synthesis of the unique structured RT-Sn@C porous fiber. The RT-Sn@C porous fiber exhibited excellent long-term cycling and rate performances. The discharge capacity of the RT-Sn@C porous fiber at the 1000th cycle was 675 mA h g-1 at a high current density of 3.0 A g-1. The RT-Sn@C porous fiber had final discharge capacities of 991, 924, 890, 848, 784, 717, 679, and 614 mA h g-1 at current densities of 0.1, 0.2, 0.3, 0.5, 1.0, 2.0, 3.0, 5.0, and 10.0 A g-1, respectively. The numerous void spaces, surrounding a Sn nanoparticle as the rattle-type particle, and the surrounding C could efficiently accommodate the volume changes of the Sn nanoparticles, improve the electrical conductivity, and enable efficient penetration of the liquid electrolyte into the structure.