Data for: Binder-free, Freestanding Cathodes Fabricated with an Ultra-rapid Diffusion of Sulfur into Carbon Nanofibers for Lithium-Sulfur Batteries
A rapid (5-second) sulfur deposition technique is demonstrated on electrospun carbon nanofibers to fabricate binder-free, freestanding cathodes for lithium-sulfur batteries. The 5-second procedure melts sulfur into carbon nanofiber mats, which play a significant role as a built-in conductive matrix to provide uninterrupted electron transport pathways throughout the electrode such that the heavy current collector is eliminated. Meanwhile, the large inter-fiber spacing facilitates electrolyte diffusion and provides sufficient space for sulfur integration during cathode fabrication and the volume expansion during lithium-sulfur redox reaction. This technique eliminates the need for slurry processing with insulating binders and toxic solvents as well as eliminating heavy current collectors. This ultra-rapid technique involving only 140 °C, 5 s, and slight pressure (< 250 psi) offers a practical approach to light-weight sulfur cathodes compared to the conventional sulfur melt deposition techniques requiring high temperatures (155 - 300 °C), long times (8 - 10 h), and heavy components in the cell assembly. The cathodes thus obtained deliver a discharge capacity of ~ 550 mA h gsulfur-1 owing to their simple construction, with 100% capacity retention at 0.5C rate over 150 cycles. This translates to ~250 mA h gelectrode-1 (based on total mass at the cathode) which is comparable to highly sophisticated electrodes when the weight of the entire electrode and current collector is considered.