Well-Defined Hierarchically Porous Double-Shell Hollow Polypyrrole@Sulfur Microspheres with Outer Sulfur Shells for Lithium-Sulfur Batteries with Superior Electrochemical Performance

Polypyrrole (PPy) hollow micro/nanospheres have been widely designed to encapsulate active sulfur as cathodes in lithium-sulfur (Li-S) batteries to inhibit the polysulfide shuttle effect. Here, for the first time, well-defined hierarchically porous double-shell hollow polypyrrole@sulfur (h-PPy@S) microspheres were fabricated as sulfur cathodes for high-performance Li-S batteries, with sulfonated polystyrene (PSS) microspheres as sacrificial templates. With an optimized outer sulfur shell, the hierarchically porous h-PPy@S cathode possessed superior electrochemical performance, in comparison with the reported S@PPy cathodes with outer PPy shells, especially the cycling stability. The superior electrochemical performance should have resulted from the unique hierarchically porous double-shell hollow nanostructure with an inner PPy shell and a thinner uniform outer S shell.