Synthesis of highly defective hollow double-shelled Co3O4−x microspheres as sulfur host for high-performance lithium-sulfur batteries

Abstract Currently, the Lithium-sulfur batteries (LSB) suffer from the issue of severe “polysulfide shuttle”, else they have a great potential to support next-generation energy storage. Herein, hollow porous double-shelled Co3O4−x microspheres with abundant oxygen deficiency were prepared for lithium polysulfides (LPS) fixation. The rational hollow porous structure facilitated sulfur loading and multiple spatial confinement on LPS was implemented by the double shells. An abundant oxygen deficiency not only promoted electronic transfer but also relieved polarization during the cycling process. Hence, the S-Co3O4−x cathode delivered satisfying cycling performance and rate capability. An initial specific capacity of 1256 mAh g−1 was obtained at 0.2 C, and the capacity of 1054 mAh g−1 was maintained even after 100 cycles. At a high c-rate of 3 C, the S-Co3O4−x electrode still exhibited a specific capacity of 780 mAh g−1.