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 TiS 2 as a conductive polysulfide adsorbent, which allows the use of a high amount of electrochemically active polysulfides in building a TiS 2 –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 LiCoO 2 . 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 .