Viet Phuong Nguyen1,2,Jae-Hyun Kim1,2,Seung-Mo Lee1,2
University of Science and Technology (UST)1,Korea Institute of Machinery & Materials (KIMM)2
Viet Phuong Nguyen1,2,Jae-Hyun Kim1,2,Seung-Mo Lee1,2
University of Science and Technology (UST)1,Korea Institute of Machinery & Materials (KIMM)2
A dense electrode with high sulfur loading is a straightforward approach to increasing the energy density of lithium-sulfur batteries, but the development of dense electrodes suffers from both fabrication challenges and electron/ion transport limitations. In addition, the shuttle effect of soluble lithium polysulfides and sluggish reaction kinetics cause declined utilization efficiency of the active material and poor cycling stability. In this study, we demonstrated that a novel heterostructure in the form of TiS<sub>2</sub> nanoribbons decorated with TiO<sub>2</sub> could function as an effective sulfur host to tackle these issues. We observed that TiO<sub>2</sub> with high adsorption capability anchors the lithium polysulfides, and TiS<sub>2</sub> with high electrical/ionic conductivity and catalytic activity can accelerate the charge transportation and enhance the kinetics of sulfur evolution reactions. Benefitting from these synergistic effects, the lithium-sulfur batteries using TiO<sub>2</sub>@TiS<sub>2</sub> heterostructures exhibited high gravimetric and volumetric energy densities of 331 Wh kg<sup>-1</sup> and 730 Wh L<sup>-1</sup>, respectively, as well as superior cyclability at a high sulfur mass loading of 7.5 mg cm<sup>-2</sup> and lean electrolyte of 2.5 µL mg<sup>-1</sup>. The electrochemical performance was comparable to or even superior to the lithium-ion and lithium-sulfur batteries reported in the literature. This work provides an effective strategy for designing stable and high-energy-density lithium-sulfur batteries for practical energy storage applications.