Department of Chemistry and Biotechnology, Yokohama National University , 79-5 Tokiwadai, Hodogaya-ku, Yokohama 240-8501, Japan.
ACS Appl Mater Interfaces. 2017 Nov 8;9(44):38477-38485. doi: 10.1021/acsami.7b11065. Epub 2017 Oct 25.
Lithium-sulfur (Li-S) batteries have attracted interest as a promising energy-storage technology due to their overwhelming advantages such as high energy density and low cost. However, their commercial success is impeded by deterioration of sulfur utilization, significant capacity fade, and poor cycle life, which are principally originated from the severe shuttle effect in relation to the dissolution and migration of lithium polysulfides. Herein, we proposed an effective and facile strategy to anchor the polysulfides and improve sulfur loading by constructing a three-dimensionally hierarchical Ni/NiS/S cathode. This self-supported hybrid architecture is sequentially fabricated by the partial sulfurization of Ni foam by a mild hydrothermal process, followed by physical loading of elemental sulfur. The incorporation of NiS, with high electronic conductivity and strong polysulfide adsorption capability, can not only empower the cathode to alleviate the shuttle effect, but also afford a favorable electrochemical environment with lower interfacial resistance, which could facilitate the redox kinetics of the anchored polysulfides. Consequently, the obtained Ni/NiS/S cathode with a sulfur loading of ∼4.0 mg/cm demonstrated excellent electrochemical characteristics. For example, at high current density of 4 mA/cm, this thick cathode demonstrated a discharge capacity of 441 mAh/g at the 150th cycle.
锂硫（Li-S）电池因其高能量密度和低成本等优势而引起了人们的兴趣，被认为是一种很有前途的储能技术。然而，其商业成功受到硫利用率下降、容量明显衰减和循环寿命差的阻碍，这主要源于与多硫化锂溶解和迁移有关的严重穿梭效应。在此，我们提出了一种通过构建三维分级 Ni/NiS/S 阴极来锚定多硫化物和提高硫负载量的有效且简单的策略。该自支撑混合结构通过温和水热过程部分硫化泡沫镍，然后物理加载元素硫来顺序制备。高导电性和强多硫化物吸附能力的 NiS 的加入不仅使阴极能够减轻穿梭效应，而且还提供了一个有利的电化学环境，具有更低的界面电阻，这有利于锚定的多硫化物的氧化还原动力学。因此，所获得的具有约 4.0mg/cm2 硫负载量的 Ni/NiS/S 阴极表现出优异的电化学性能。例如，在 4mA/cm 的高电流密度下，该厚阴极在第 150 次循环时的放电容量为 441mAh/g。
