Rational Design of Graphite Nanoplatelets Interlayers via a Surfactant-Controlled Strategy for Enhancing Lithium-Sulfur Batteries

Developing advanced battery interlayers is one of the promising approaches for trapping dissolved polysulfides in lithium-sulfur (Li-S) batteries. Thus far, there is a lack of cost-effective strategies to characterize the comprehensive properties of interlayers and understanding of the roles that the interlayer properties play in the battery performance. Herein, we design a surfactant-controlled strategy to tune the structures/properties of the interlayers and establish the relationships among structure, property, and performance through comprehensive characterizations. It is surprisingly found that only with a specific surfactant, gelatin protein, a robust and self-assembled porous graphite nanoplatelets (GNPs) interlayer can be achieved. Meanwhile, benefiting from the rich functional groups of protein, the protein functionalization of GNPs leads to not only good adhesion to a separator for the GNPs interlayer but also strong polysulfide-trapping ability. As a result, by adding the protein-functionalized GNPs interlayer to a Li-S battery, the electrochemical performance is obviously enhanced, owing to the abilities of the interlayer for trapping polysulfides and facilitating ion transport simultaneously. This study correlates the physicochemical properties of interlayers with their electrochemical performance and is of universal significance for design and fabrication of advanced battery interlayers.