Elucidating the dominant role of all-amorphous heterostructure on optimized built-in electric field with abundant active sites for advanced lithium–sulfur batteries

Abstract

While various transition metal compound-based electrocatalysts have been developed to mitigate the shuttle effect of lithium–sulfur (Li–S) batteries, few studies have examined the effectiveness of their crystal structures. Herein, by integrating amorphous MoS2 nanosheets and TiO2 layers, an all-amorphous heterostructure is designed as a multifunctional electrocatalyst. The highly disordered atomic arrangement of the components provides abundant active sites and creates additional energy levels within the band gaps. Moreover, this unique crystal structures shift the Fermi level. Due to these synergistic effects, a well-aligned strong built-in electric field is generated, thereby exhibiting specific capacity of 1135 mA h g–1 at a current rate of 1 C, along with a stable long-term lifespan of 500 cycles at 2 C. This work provides a novel strategy for optimizing built-in electric field and amplifying active sites by constructing an all-amorphous heterostructure, which is crucial for the advanced Li–S batteries.