Entrapping polysulfides via S, N-coordinated supermolecule towards enhanced Li-S kinetics

Abstract Currently, the urgent requirement of high-energy–density storage devices for large-grid applications has been brought to public attention. Lithium-sulfur (Li-S) batteries are one of the most recognized candidates to substitute for the state-of-the-art lithium-ion (Li-ion) batteries. To conquer the dogged polysulfide shuttling in Li-S cells, a supramolecular crystal was synthesized via the coordination of a thiol ligand with nickel to generate a unique cage-like cluster in the form of N4-Ni∙∙∙Ni-S4 as the precursor of organosulfur, in which sulfur was anchored on nitrogen sites. The organosulfur undergoes changes in both the configuration and electron distribution upon lithiation/delithiation process, which can strengthen entrapment of polysulfides, boost efficient sulfur conversion and promote the reaction kinetics of the cathodes. The Li-S cells were demonstrated a high initial discharge capacity of 1354.9 mAh g−1 at 0.2 C and a long-term lifespan of 1000 cycles at 2 C. The high-loading sulfur cathodes of 8.6 mg cm−2 is capable of delivering an areal capacity as high as 9.1 mAh cm−2. Combining with the advantages of low cost and facile synthesis, such organosulfur is of great promising perspective in further boosting the commercial realization of Li-S batteries.