Modified separators coated with a Ca(OH)2–carbon framework derived from crab shells for lithium–sulfur batteries

Abstract

Lithium–sulfur (Li–S) batteries have been considered as promising candidates for next-generation energy storage owing to the remarkably high theoretical specific capacity and energy density of sulfur. However, the shuttle effect of lithium polysulfides hampers their commercial application. Here, a Ca(OH)₂–carbon framework derived from crab shells is successfully used to design a modified separator for Li–S batteries. Benefiting from the effective dispersal of Ca(OH)₂ in the conductive carbon framework, the Ca(OH)₂–carbon framework confers two benefits: first, it facilitates electron and ion transfer during redox reactions, and second, it efficiently traps the dissolved polysulfides. An enhanced Li–S performance is achieved by the utilization of a Ca(OH)₂–carbon framework-modified separator, resulting in an initial capacity of 1215 mA h g⁻¹ and a high reversible capacity of 873.5 mA h g⁻¹ after 250 cycles at a rate of 0.5C. The results of this work show that Ca(OH)₂–carbon frameworks derived from crab shells could be promising nanostructured materials to improve the performance of Li–S batteries.