Graphdiyne nanostructure for high-performance lithium-sulfur batteries

Abstract

The advantages of an enhanced inner mass transfer in the primary nanostructure have been ignored for a long time in the lithium-sulfur (Li-S) batteries. This paper demonstrates the construction of Nafion@graphdiyne core-shell nanostructure, which first embeds a polyanion (Nafion) seamlessly in an all-carbon nanostructure of graphdiyne. The graphdiyne acts as the conductive and mechanical backbone to store sulfur and offers active epicenters (sp-hybridized carbon) for the cathodic reaction. The embedded Nafion greatly enhances the inner mass transfer behavior in the primary nanostructure, thus improves the phase transformation reaction, leading to the efficient suppression of the polysulfides shuttle. The Li-S battery incorporating such core-shell nanostructure performs high retention in its capacity even after 800 cycles at high current densities (0.5C and 1C). A high volume capacity of 1832 A h L−1, which is 53% of the theoretical value of sulfur is obtained succesfully. This core-shell nanostructure appears to produce new phenomena, properties, and functions. It can be applicable in, for example, catalysis, fuel cells, and supercapacitors, as well as batteries.