Interlinked Carbon Nanocages-Coated Separator as an Efficient Trap for Soluble Polysulfides in a Lithium–Sulfur Battery

The utilization of carbon-coating materials to inhibit the shuttle effect of the polysulfides is an important theme for lithium–sulfur (Li–S) batteries. However, the structure of carbon materials and the way that they are packed are important factors, because they determine the number and size of pores of future layers and, consequently, the permeability of ions. This work presents interlinked carbon nanocages (IL-CNCs) as the coating materials for the separators of Li–S batteries. The surface morphology, pore structure, and cyclic performances as well as the rate properties of the composite separators were fully analyzed. IL-CNCs coatings offer abundant surfaces and an interface to trap polysulfide as well as a long transmission distance to prevent polysulfide ions from penetrating the membrane. The IL-CNCs-coated separators exhibit excellent electrochemical properties in different rates, a long cycling time at 1 C, and a high cathode loading. Moreover, only 0.025 mg cm–2 of IL-CNCs coating can obtain a reversible capacity of 747 mAh g–1 after 100 cycles at 0.2 C.