Sn-encapsulated N-doped porous carbon fibers for enhancing lithium-ion battery performance.

Tin (Sn) has wide prospects in applications as an anode electrode material for Li-ion batteries, due to its high theoretical specific capacity. However, the large volume expansion of Sn during the charge-discharge process causes a performance reduction of lithium-ion batteries (LIBs). Here, Sn encapsulated N-doped porous carbon fibers (Sn/NPCFs) were synthesized through an electrospinning method with a pyrolysis process. This structure was beneficial for the lithium ion/electron diffusion and buffered the large volume change. By adjusting the amount of Sn, the hybrid carbon fibers with different Sn/carbon ratios could be prepared, and the morphology, composition and properties of the Sn/NPCFs were characterized systematically. The results indicated that the Sn/NPCFs with a Sn-precursor/polymer weight ratio at 0.5 : 1 showed the best cycling stability and specific capacity, preserving the specific capacity of 400 mA h g at the current density of 500 mA g even after 100 cycles.