Handheld spraying of g-C3N4 nanosheets on cathode for high-performance lithium-sulfur batteries

Lithium-sulfur batteries (Li-S) have been regarded as one of the most promising candidates for next-generation energy-storage systems due to its high theoretical energy density (2600 Wh/kg). However, the “shuttle effect” and the resulting self-discharge hinder the commercialization of Li-S batteries. In this study, a facile, inexpensive, and scalable spray-coating method was developed to cover a cathode with carbon nitride film (g-C3N4). Because of the strong adsorption of polysulfides by carbon nitride, the S-GF/C3N4 cathode exhibited a high reversible capacity of 927 mAh/g at 0.2 C and long cyclic stability of 720 mAh/g after 280 cycles with a high capacity retention up to 78% with the sulfur loading of 5 mg/cm2. This study presents a new pervasive spray-coating method to facilitate simple and large-scale membrane modification and to enable the practical application of Li-S batteries.