High electrochemical activity of Li₂S₂ linking two-dimensional tungsten boride nanosheet enables high-loading and long-lasting lithium-sulfur batteries

The Li₂S-based cathodes with a high theoretical capacity of 1,166 mAh/g are regarded as the commercially available lithium-sulfur battery that can be coupled with Li-free anodes to avoid the safety concern of lithium metal. However, the instinct Li₂S passivation leads to a high activation potential and low sulfur utilization with the notorious polysulfide migration. Herein, the single-atom tailoring strategy in designing liquid Li₂S₂ catholyte is created without the use of any complicated manufacturing processes or additives, where the Li₂S₂ cell enables the 3.0 V activation voltage without potential barrier. Meanwhile, the conductive and polar tungsten boride offer the active center to anchor polysulfides migration. As expected, the tungsten boride-Li₂S₂ cathode exhibits excellent cycling stability, impressive cycling performance without initial potential barrier.