Designing an interlayer of reduced graphene oxide aerogel and nitrogen-rich graphitic carbon nitride by a layer-by-layer coating for high-performance lithium sulfur batteries

Abstract

Herein, reduced graphene oxide aerogel (GA) with 3D interconnected conductive and porous structure was used as a host of sulfur (S@GA cathode). GA was also used together with nitrogen-rich graphitic carbon nitride (GCN) as the interlayer accommodating the soluble lithium polysulfides (LPSs). The interlayer was fabricated by a layer-by-layer coating technique on the flexible and processible carbon fiber paper (CFP) substrate. The interlayer inserted between the cathode and the separator provides a strong lithium polysulfide adsorptivity. Adsorptive LPS species on the interlayer were also investigated by an ex situ X-ray photoelectron spectroscopy. After finely tuned, the as-fabricated LSB using the S@GA cathode with the GA/GCN interlayer exhibits 75% higher specific capacity than the cell without interlayer. It has a low capacity fading of 0.056% per cycle after tested for 800 cycles. Our new design and configuration of LSB may practically be used in high-energy applications since it can effectively address many issues of the current LSBs.