Tin Nanodots Encapsulated in Porous Nitrogen-Doped Carbon Nanofibers as a Free-Standing Anode for Advanced Sodium-Ion Batteries.

Ultrasmall Sn nanodots (1-2 nm) are homogeneously encapsulated in porous N-doped carbon nanofibers using a simple and scalable electrospinning method. The composite nanofibers weave into flexible free-standing membrane and can be directly used as binder- and current collector-free anode for Na-ion batteries, exhibiting excellent electrochemical performance with high reversible capacity, exceptional rate capability, and ultralong cycle life.