Microreactor\nStrategy to Capture Sulfur for Lithium–Sulfur\nBatteries

The limited conductivity and shuttle\neffect tie the sulfur cathode\ndown. Carbon nanofibers (CNFs) offer long-range conductivity with\ncost effectiveness but fail for the wanted backing since they are\nintertwined with each other, which makes it difficult for sulfur to\npermeate the mass of the CNF matrix. Dissolving or melting sulfur\nand immersing it in the bulk of CNFs cannot avoid sulfur segregation.\nBy nanosizing sulfur and loading it into the bulk of the CNFs with\nthe assistance of surfactants, we propose a microreactor strategy\nto address these challenges. Due to the spatial constraints within\nthe S@CNF microreactors, the nanostructured sulfur can be sintered\nat high temperatures without significant mass loss. As a result, not\nonly is the electrical conductivity improved but also the shuttle\neffect is obviously confined in microreactors, enhancing cycle performance\nat an elevated S/C ratio of 8:2. The diffusion coefficient and activation\nenergy characterized by the Randles–Sevcik equation and operando\napproaches, respectively, validate the enhancement of dynamics, which\ncan be ascribed to the promoting effect of electronic transitions\non ionic diffusion. The analysis of optical and electrochemical band\ngaps confirms this point of view. Thereby, using the microreactor\nstrategy, we turn the adverse mass of the CNFs into favorable factors.