Conductive and Polar Titanium Boride as a Sulfur Host for Advanced Lithium-Sulfur Batteries

Lithium-sulfur batteries are the most promising candidates for advanced electrochemical energy storage systems benefiting from their high energy density and low cost of sulfur. Improving the conductivity of sulfur cathode and stabilizing the polysulfide shuttle are the key factors for obtaining high-performance lithium-sulfur batteries. Herein, metallic and polar TiB2 nanomaterials are applied for the first time as sulfur hosts. The 70S/TiB2 composite exhibits a long-term cycling stability up to 500 cycles at the current density of 1 C. It is worth noting that even when the sulfur areal mass loading is up to 3.9 mg cm(-2), a stable capacity of 837 mA h g(-1) can be still maintained after 100 cycles. The outstanding electrochemical performance can be attributed to the strong anchoring effect of TiB2 to lithium polysulfides, which is confirmed by the X-ray photoelectron spectroscopy analyses and theoretical calculations with a favorable surface-passivated chemistry. The study presented here will shed a new light for metal borides as hosts to improve the cycling life of lithium-sulfur batteries and provide a deep comprehension of the instinct interaction evolution at a molecular level, which is invaluable in the material rational fabrication for future high-performance Li-S batteries.