Unearth the understanding of interfacial engineering techniques on nano sulfur cathodes for steady Li-S cell systems

Inherent/tough cell issues such as the troublesome shuttling of intermediate Li2Sn (n = 3-8) and the inferior conductivity of S/Li2S are still hardly eliminated in rechargeable Li-S cells. Continually rationalizing the cathodes via innovative interfacial engineering would, thereby, be an indispensable propellant for expediting cell kinetics for practical utilizations. By the deliberate choice of nano S cathodes as a typical fundamental research paradigm, we herein affirm a special controllable engineering protocol via (i) in situ pyrrole molecules polymerization on S nanoparticles and (ii) osmosis-driven procedures where inner high-density S atoms tend to be evenly etched/lost. Parameters such as the aging time and persulfate salt addition are verified as dominant factors to tune the exterior shell thickness and S content in samples. To further strengthen the cathode structural integrity and conductivity, virus-like hierarchical S@PPy@ZnIn2S4 products are constructed by the intimate growth of conductive/polar ZnIn2S4 nanolayers on all exterior S@PPy surfaces. Given the positive collaborations from electrode functionality integration and architecture setup, such interface-reinforced cathodes showcase prominent Li-storage performances on either long-lasting cyclic stability/endurance or rate capabilities. This work provides insights into delicate engineering techniques on elemental S for superior Li-S cell systems, and may also open up a smart "nano-interface-level"platform for more artificial/control designs toward other relatively inert molecular nanocrystals.