Lithium-sulfur batteries have been investigated as promising electrochemical-energy storage systems owing to their high theoretical energy density. Sulfur-based cathodes must not only be highly conductive to enhance the utilization of sulfur, but also effectively confine polysulfides to mitigate their dissolution. A new physical and chemical entrapment strategy is based on a highly efficient sulfur host, namely hollow carbon nanofibers (HCFs) filled with MnO2 nanosheets. Benefiting from both the HCFs and birnessite-type MnO2 nanosheets, the MnO2 @HCF hybrid host not only facilitates electron and ion transfer during the redox reactions, but also efficiently prevents polysulfide dissolution. With a high sulfur content of 71 wt % in the composite and an areal sulfur mass loading of 3.5 mg cm(-2) in the electrode, the MnO2 @HCF/S electrode delivered a specific capacity of 1161 mAh g(-1) (4.1 mAh cm(-2) ) at 0.05 C and maintained a stable cycling performance at 0.5 C over 300 cycles.

Rationally designed hollow nanostructures are attractive host materials for the sulfur cathode in lithium–sulfur batteries.

Lithium-sulfur (Li-S) batteries have been considered as a promising candidate for next-generation electrochemical energy-storage technologies because of their overwhelming advantages in energy density. Suppression of the polysulfide dissolution while maintaining a high sulfur utilization is the main challenge for Li-S batteries. Here, we have designed and synthesized double-shelled nanocages with two shells of cobalt hydroxide and layered double hydroxides (CH@LDH) as a conceptually new sulfur host for Li-S batteries. Specifically, the hollow CH@LDH polyhedra with complex shell structures not only maximize the advantages of hollow nanostructures for encapsulating a high content of sulfur (75 wt %), but also provide sufficient self-functionalized surfaces for chemically bonding with polysulfides to suppress their outward dissolution. When evaluated as cathode material for Li-S batteries, the CH@LDH/S composite shows a significantly improved electrochemical performance.

A pyrolyzed polyacrylonitrile/selenium disulfide composite cathode manifests high performance for both lithium and sodium storage.

This work proposes a hierarchically structured cathode that simultaneously tackles several problems associated with high-sulfur-loading electrodes for lithium-sulfur batteries. This work overcomes the major limitations associated with other host materials of sulfur, and opens up new prospects for constructing more efficient nanostructures for moderating the diffusion loss of polysulfides and enhancing the reaction kinetics of sulfur. We hope this work will inspire scientists to develop better batteries to satisfy the world demand for energy storage.