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.