Materials Science and Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712, USA.
State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, P. R. China.
Adv Mater. 2017 Sep;29(34). doi: 10.1002/adma.201702707. Epub 2017 Jul 10.
Owing to the high theoretical specific capacity (1675 mA h g ) 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@Fe O (YSC@Fe O ) 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 Fe O 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 Fe O 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@Fe O cathodes support high sulfur content (80 wt%) and loading (5.5 mg cm ) 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.
由于具有高理论比容量（1675 mA h g ）和低成本，锂硫（Li-S）电池为下一代储能提供了优势。然而，硫正极的多硫化物溶解和低电子电导率限制了 Li-S 电池的实际应用。为了解决这些问题，设计了具有核壳结构的蛋黄壳型碳@Fe O (YSC@Fe O )纳米盒作为高效的 Li-S 电池硫载体。通过碳壳的物理捕获和与 Fe O 核的强化学相互作用，这种独特的结构固定了活性物质并抑制了多硫化物中间体的扩散。此外，由于其高导电性，碳壳和极性 Fe O 核促进了电子/离子的快速传输，并在充放电过程中促进了活性物质的连续再激活，从而提高了电化学利用率和可逆性。由于这些优点，S/YSC@Fe O 正极支持高硫含量（80wt%）和负载量（5.5mg cm ），并表现出高比容量、优异的倍率性能和长循环稳定性。这项工作为设计基于碳/金属氧化物的具有核壳结构的蛋黄壳型框架提供了新的视角，作为具有优异电化学性能的先进 Li-S 电池的高硫负载量宿主。
