Catalytic conversion of polysulfides by atomic layer deposition derived titanium nitride for high-performance lithium-sulfur batteries

Abstract

Lithium-Sulfur (Li-S) batteries as the next-generation battery system have an ultrahigh theoretical energy density. However, the limited conversion of polysulfides in sulfur cathodes deteriorates the performance of Li-S batteries. In this study, we develop a novel titanium nitride (TiN) catalyst for sulfur cathodes via atomic layer deposition (ALD). The synthesized ALD-TiN catalyst shows controllable ultrafine particle size (<2 nm) and uniform distribution at the nanoscale in the carbon matrix. Combined with electrochemical analysis and multiple post-characterization techniques, ALD-TiN demonstrates an excellent catalytic effect to facilitate the nucleation and deposition of Li₂S, which effectively suppresses the dissolution and shuttle of polysulfides. The as-prepared sulfur cathodes, with the assistance of TiN catalyst, exhibit excellent cycling performance at a high rate (4 C) and deliver 200% higher discharge capacity than the pristine Sulfur-pristine porous carbon composite cathodes.