Yolk–Shelled C@Fe3O4 Nanoboxes as Efficient Sulfur Hosts for High-Performance Lithium–Sulfur Batteries

Owing to the high theoretical specific capacity (1675 mA h g⁻¹) and low cost, lithium–sulfur (Li–S) batteries offer advantages for next-generation energy storage. However, the polysulfide dissolution and low electronic conductivity of sulfur cathodes limit the practical application of Li–S batteries. To address such issues, well-designed yolk–shelled carbon@Fe₃O₄ (YSC@Fe₃O₄) nanoboxes as highly efficient sulfur hosts for Li–S batteries are reported here. With both physical entrapment by carbon shells and strong chemical interaction with Fe₃O₄ cores, this unique architecture immobilizes the active material and inhibits diffusion of the polysulfide intermediates. Moreover, due to their high conductivity, the carbon shells and the polar Fe₃O₄ cores facilitate fast electron/ion transport and promote continuous reactivation of the active material during the charge/discharge process, resulting in improved electrochemical utilization and reversibility. With these merits, the S/YSC@Fe₃O₄ cathodes support high sulfur content (80 wt%) and loading (5.5 mg cm⁻²) and deliver high specific capacity, excellent rate capacity, and long cycling stability. This work provides a new perspective to design a carbon/metal-oxide-based yolk–shelled framework as a high sulfur-loading host for advanced Li–S batteries with superior electrochemical properties.

A well-designed yolk–shelled carbon@Fe₃O₄ (YSC@Fe₃O₄) nanobox is employed as a highly efficient sulfur host for Li–S batteries. Benefiting from the strong polysulfide adsorption and high conductivity of YSC@Fe₃O₄, the S/YSC@Fe₃O₄ cathodes support high sulfur content (80 wt%) and loading (5.5 mg cm⁻²), providing new insights to develop high-performance Li−S batteries.

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