Carbonized regenerated silk nanofiber as multifunctional interlayer for high-performance lithium-sulfur batteries

Problems regarding the low conductivity of sulfur, dissolution and diffusion of polysulfides in liquid electrolytes, and corrosion of the lithium interface hinder the advancement of lithium-sulfur batteries for next-generation energy storage. The development of a new cell configuration is a simple and effective method of resolving the above problems. Here, we use electrospun carbonized silk nanofiber film as the cathode- and anode-interlayer for lithium-sulfur batteries. The interwoven network and microprous structure of interlayer improves the sulfur cathode conductivity and curbs the “shuttle effect”; the anode-interlayer acts as a protective layer to reduce the lithium corrosion. Having a sulfur loading of 2.0 mg cm-2, the sulfur cathode-interlayer combined with the lithium anode-interlayer shows a reversible capacity of 799 mA h g-1 after 200 cycles at 0.2 C with 0.018% average capacity loss per cycle. At a rate of 1.0 C, the discharge capacity remains at 655 mA h g-1 after 500 cycles with a Coulombic efficiency of 97.3%. This new cell configuration with a double-interlayer based on carbonized silk nanofiber opens up another path for advanced lithium-sulfur batteries to deal with a variety of challenges. [Display omitted] •Silk nanofibers are formed by electrospinning method.•As-obtained Carbonized silk nanofiber mats are used as freestanding interlayer.•Double interlayers were introduced to improve the performance of Li–S batteries.