Advanced Lithium–Sulfur Batteries Enabled by a Bio-Inspired Polysulfide Adsorptive Brush

Issues with the dissolution and diffusion of polysulfides in liquid organic electrolytes hinder the advance of lithium–sulfur batteries for next-generation energy storage. To trap and re-utilize the polysulfides without hampering lithium ion conductivity, a bio-inspired, brush-like interlayer consisting of zinc oxide (ZnO) nanowires and interconnected conductive frameworks is proposed. The chemical effect of ZnO on capturing polysulfides has been conceptually confirmed, initially by using a commercially available macroporous nickel foam as a conductive backbone, which is then replaced by a free-standing, ultra-light micro/mesoporous carbon (C) nanofiber mat for practical application. Having a high sulfur loading of 3 mg cm⁻², the sulfur/multi-walled carbon nanotube composite cathode with a ZnO/C interlayer exhibits a reversible capacity of 776 mA h g⁻¹ after 200 cycles at 1C with only 0.05% average capacity loss per cycle. A good cycle performance at a high rate can be mainly attributed to the strong chemical bonding between ZnO and polysulfides, fast electron transfer, and an optimized ion diffusion path arising from a well-organized nanoarchitecture. These results herald a new approach to advanced lithium–sulfur batteries using brush-like chemi-functional interlayers.