Highly Conductive Porous Transition Metal Dichalcogenides via Water Steam Etching for High-Performance Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries show significant advantages for next-generation energy storage systems owing to their high energy density and cost effectiveness. The main challenge in the development of long-life and high-performance Li-S batteries is to simultaneously facilitate the redox kinetics of sulfur species and suppress the shuttle effect of polysulfides. In this contribution, we present a general and green water-steam-etched approach for the fabrication of H- and O-incorporated porous TiS2 (HOPT). The conductivity, porosity, chemisorptive capability, and electrocatalytic activity of HOPT are enhanced significantly when compared with those of raw TiS2. The synthetic method can be expanded to the fabrication of other highly conductive transition metal dichalcogenides such as porous NbS2 and CoS2. The as-obtained HOPT can serve as both a substitute of conductive agents and an additive of interlayer materials. The optimal electrode delivers discharge capacities of 950 mA h g-1 after 300 cycles at 0.5 C and 374 mA h g-1 after 1000 cycles at 10 C. Impressively, an unprecedented reversible capacity of 172 mA h g-1 is achieved after 2500 cycles at 30 C, and the average capacity fading rate per cycle is as low as 0.015%. Importantly, four half-cells based on this electrode in series could drive 60 light-emitting diode indicator modules (the nominal power 3 W) after 20 s of charging. The instantaneous current and power of this device on reaching 275 A g-1 and 2611 W g-1, respectively, indicate outstanding high-power discharge performance and potential applications in electric vehicles and other large-scale energy storage systems.