Revisiting the Nanofluid Behavior of Polysulfides in Carbon-Based Interlayers: Longitudinal Osmotic Diffusion and Transverse Radiation-Distribution Induced by Mn-Based Catalysts

Carbon-based interlayer as the secondary current collector is a typical approach for suppressing the polysulfide shuttle effect in lithium-sulfur batteries (LSBs). The effective operating lifespan is determined by the balance between the local polysulfide concentration and bearing capacity of interlayers. However, the microscopic diffusion of polysulfides within interlayers under multiple force fields remains unclear, particularly the effect of catalyst on the multi-scale diffusion behavior. Herein, the first identification is reported of the polysulfide diffusion in interlayer with a coupling effect of longitudinal osmotic and transverse radioactive diffusion through revisiting Mn-based catalysts (Mn-X, X = N, O, or P). In addition to electric field forces during charging and discharging, the free polysulfides sustain transverse tension, leading to radiation diffusion behavior. This adaptive adjustment optimizes polysulfide distribution, mitigating the risk of interlayer deactivation caused by excessive local concentration. The extent of lateral radioactive diffusion is positively correlated with the physicochemical adsorption capacity of catalysts for polysulfides in the interlayer. Specifically, the interlayer with stronger static adsorption for polysulfides demonstrates a broader radiation diffusion range. This work re-evaluates the polysulfide diffusion behavior within the interlayers, further guiding the design of high performance secondary current collector.