W18O49 nanowire composites as novel barrier layers for Li–S batteries based on high loading of commercial micro-sized sulfur†
Li–S batteries are regarded as one of the most promising energy-storage devices due to their high theoretical energy density, five times higher than that of lithium-ion batteries (2600 vs. ∼500 W h kg−1). However, the polysulfide shuttle effect is the primary challenge for future applications of Li–S batteries. Herein, a novel barrier layer material, nonstoichiometric W18O49 nanowires, is reported to alleviate the undesirable shuttle effect, thereby largely boosting the specific capacity and cyclability of Li–S batteries. Without particular cathode design, the introduction of W18O49 nanowires enables the commercially available micro-sized sulfur cathode with 70% sulfur loading to deliver a respectable initial discharge capacity of 1142 mA h g−1 and retain a specific capacity of about 809 mA h g−1 after 50 cycles, even at a current density of 0.5 A g−1. To the best of our knowledge, such a capacity fading for Li–S batteries based on high loading of commercial micro-sized sulfur has been rarely reported.