Atomic-Scale Interface Engineering to Construct Highly Efficient Electrocatalysts for Advanced Lithium-Sulfur Batteries.

Abstract

Heterostructure materials integrating the unique physical and chemical properties of each heterogeneous component are highly promising for optimizing lithium-sulfur batteries. However, precisely regulating the interface microstructures of heterostructures at the atomic scale still lacks effective means, and the law of interface microstructures affecting the properties of heterostructures is not yet clearly understood. Herein, an atomic-scale regulation strategy is presented to construct heterostructure materials containing the high-energy Fe2O3-CeO2 interfaces with specific atomic arrangements using a high-index faceted Fe2O3 octadecahedron as the substrate for the heterogrowth of CeO2 nanocrystals, which effectively improves the redox kinetics of sulfur species in lithium-sulfur batteries. Experimental and theoretical calculations reveal that the strong interface interactions, characterized by plentiful electron transfer between Fe2O3 and CeO2, render the high-energy Fe2O3-CeO2 interfaces with good adsorption properties and high catalytic activity for various sulfur species. Attributed to the abundant high-energy Fe2O3-CeO2 interfaces, the Fe2O3-CeO2 octadecahedra effectively inhibit the shuttling of polysulfide and significantly accelerate the interconversion of sulfur species. The incorporation of these high-activity electrocatalysts enables the batteries to deliver superb long-term cyclic stability with a low average capacity fading of 0.016% per cycle over 2000 cycles at 2.0 C. Even at a low electrolyte/sulfur ratio of 4.3 μL mg-1, the batteries with a sulfur loading of 8.79 mg cm-2 maintain an areal capacity as high as 7.53 mAh cm-2 after 100 cycles. This study achieves the precise atomic-scale regulation of the interface microstructures, deepening the comprehending of the electrocatalytic conversion of sulfur species associated with the interface microstructures while delivering valuable guidance for the rational construction of advanced electrocatalysts for Li-S batteries.