TiS₂-Polysulfide Hybrid Cathode with High Sulfur Loading and Low Electrolyte Consumption for Lithium-Sulfur Batteries

Sulfur cathodes have a high theoretical capacity of 1675 mAh g^-1, making the lithium-sulfur batteries a promising technology for future energy-storage devices. However, their commercial viability is faced with challenges arising from intrinsic electrochemical instabilities and inappropriate cell fabrication parameters. We report here the feasibility of employing TiS₂ as a conductive polysulfide adsorbent, which allows the use of a high amount of electrochemically active polysulfides in building a TiS₂-polysulfide hybrid cathode. The hybrid cathode exhibits long cycle stability at a C/5 rate over 200 cycles with a high areal capacity and energy density of, respectively, 10 mAh cm^-2 and 20 mWh cm^-2, exceeding those of commercial LiCoO₂. Such an enhanced electrochemical performance is obtained in cells with a high sulfur content (65 wt %), high sulfur loading (12 mg cm^-2), high sulfur mass (12 mg/cathode), and a low electrolyte/sulfur ratio of just 5 μL mg^-1.