Manipulating Sulfur Mobility Enables Advanced Li-S Batteries

Rational design of lithium-sulfur batteries calls for enhancing local sulfur mobility and electrocatalysis while suppressing global sulfur mobility (GSM) from cathode to anode and within cathode without sacrificing volumetric or gravimetric capacities. A multifunctional interlayer composed of electrochemically active Mo₆S₈ with fast topotactic/intercalation reactions, strong lithium polysulfide binding, and high electronic conductivity addresses these challenges. The electrocatalytic Li_xMo₆S₈ interlayer successfully solves the harmful stratification by preventing the Li₂S clogging at the cathode/separator interface, thus resulting in a superior rate capability up to 4 C. Remarkably, the Li_xMo₆S₈ interlayer works well with the calendered high-loading sulfur cathode with much improved volumetric energy density at a pouch-cell level. An excellent capacity retention with high initial capacity is also achieved with high-sulfur-loading cathode and lean electrolyte.