Clustered-Microcapsule-Shaped Microporous Carbon-Coated Sulfur Composite Synthesized via in Situ Oxidation

Hollow materials as sulfur hosts have been intensively investigated to address the poor cycling stabilities of Li-S batteries. Herein, we report an enhanced hollow framework to improve the applicability of the sulfur confinement. A clustered-microcapsule-shaped microporous carbon coated sulfur (CM-S@MPC) composite is prepared from the clustered zinc sulfide precursor, through an in situ oxidation process. The high specific surface area and the in situ preparation guarantee the uniform distribution of sulfur inside the carbon microcapsule, even under a higher sulfur content of 83 wt %. In addition, the interconnected frame constructed by the stacking of carbon microcapsules also mitigates the lithium polysulfide loss by setting interlayered hurdles on their pathway along the outward diffusion. Hence, these enable a full demonstration of excellent cycling stability, compared to the control sample obtained via physical sulfur infiltration. The outstanding decay rate of 0.039% per cycle is achieved during 700 cycles at 1 C, even under high sulfur loading.