State Key Laboratory of Medicinal Chemical Biology, Nankai University, 300350, Tianjin, China.
School of Energy and Environmental Engineering, Hebei University of Technology, Tianjin, 300071, China.
Adv Sci (Weinh). 2023 May;10(14):e2207442. doi: 10.1002/advs.202207442. Epub 2023 Mar 18.
For practical lithium-sulfur batteries (LSBs), the high sulfur loading and lean-electrolyte are necessary conditions to achieve the high energy density. However, such extreme conditions will cause serious battery performance fading, due to the uncontrolled deposition of Li S and lithium dendrite growth. Herein, the tiny Co nanoparticles embedded N-doped carbon@Co S core-shell material (CoNC@Co S NC) is designed to address these challenges. The Co S NC-shell effectively captures lithium polysulfides (LiPSs) and electrolyte, and suppresses the lithium dendrite growth. The CoNC-core not only improves electronic conductivity, but also promotes Li diffusion as well as accelerates Li S deposition/decomposition. Consequently, the cell with CoNC@Co S NC modified separator delivers a high specific capacity of 700 mAh g with a low-capacity decay rate of 0.035% per cycle at 1.0 C after 750 cycles under a sulfur loading of 3.2 mg cm and a E/S ratio of 12 µL mg , and a high initial areal capacity of 9.6 mAh cm under a high sulfur loading of 8.8 mg cm and a low E/S ratio of 4.5 µL mg . Besides, the CoNC@Co S NC exhibits an ultralow overpotential fluctuation of 11 mV at a current density of 0.5 mA cm after 1000 h during a continuous Li plating/striping process.
对于实用的锂硫电池 (LSB)，高硫载量和贫电解液是实现高能量密度的必要条件。然而，在如此极端的条件下，由于 Li S 的不可控沉积和锂枝晶的生长，电池性能会严重衰减。在此，设计了一种微小的 Co 纳米颗粒嵌入 N 掺杂碳@Co S 核壳材料（CoNC@Co S NC）来解决这些挑战。Co S NC 壳有效地捕获了多硫化锂 (LiPS) 和电解液，并抑制了锂枝晶的生长。CoNC 核不仅提高了电子导电性，而且促进了 Li 的扩散以及 Li S 的沉积/分解。因此，在硫载量为 3.2 mg cm 和 E/S 比为 12 µL mg 的情况下，负载量为 3.2 mg cm、E/S 比为 12 µL mg 的情况下，经过 750 次循环后，具有 CoNC@Co S NC 改性隔膜的电池在 1.0 C 下以 0.035%/循环的低容量衰减率提供了 700 mAh g 的高比容量，在硫载量为 8.8 mg cm 和 E/S 比为 4.5 µL mg 的高硫载量下，初始面积容量为 9.6 mAh cm。此外，在连续 Li 电镀/剥离过程中，在电流密度为 0.5 mA cm 时，CoNC@Co S NC 的过电位波动低至 11 mV，持续 1000 h。
