Porous Hollow Carbon Aerogel-Assembled Core@Polypyrrole Nanoparticle Shell as an Efficient Sulfur Host through a Tunable Molecular Self-Assembly Method for Rechargeable Lithium/Sulfur Batteries

Lithium-sulfur (Li-S) batteries are fascinating as next-generation high specific energy density storation devices. Herein, we report the fabrication of a three-dimensional porous hollow core@shell structure composed of a carbon aerogel assembled core etched via nano-CaCO3 and a polypyrrole nanoparticle shell as a sulfur scaffold for Li-S batteries. The as-prepared sulfur cathodes exhibit excellent reversible capacity (1031.9 mAh g(-1) at 0.1 C), outstanding rate capability (566.5 and 477.2 mAh g(-1) at 1 and 2 C, respectively), and superior cycling stability (74.2% capacity retention rate at 1 C). The improved electrochemical performance can be attributed to the extraordinary core-shell structure: the honeycomb-like carbon aerogel core provides fast transportation for the Li+/e-, and even sufficient free space for the volume expansion; the polypyrrole nanoparticle shell acts not only as a physical obstacle but also as a polar material to restrict the shuttling of polysulfides by chemical interaction. These inspiring results specify that such electrodes could empower high performance, fast charging, and flexible Li-S batteries through a tunable molecular self-assembly method to clad strong polar material on carbon materials.