State Key Laboratory of Organic-Inorganic Composites, Beijing Key Laboratory of Electrochemical Process and Technology for Materials , Beijing University of Chemical Technology , Beijing 100029 , China.
School of Materials Science & Engineering, Beijing Key Laboratory of Environmental Science and Engineering , Beijing Institute of Technology , Beijing 100081 , China.
ACS Appl Mater Interfaces. 2018 Apr 4;10(13):10882-10889. doi: 10.1021/acsami.8b00225. Epub 2018 Mar 26.
With the high energy density of 2600 W h kg, lithium-sulfur (Li-S) batteries have been considered as one of the most promising energy storage systems. However, the serious capacity fading resulting from the shuttle effect hinders its commercial application. Encapsulating small S molecules into the pores of ultramicroporous carbon (UMC) can eliminate the dissolved polysulfides, thus completely inhibiting the shuttle effect. Nevertheless, the sulfur loading of S/UMC is usually not higher than 1 mg cm because of the limited pore volume of UMC, which is a great challenge for small sulfur cathode. In this paper, by applying ultralight 3D melamine formaldehyde-based carbon foam (MFC) as a current collector, we dramatically enhanced the areal sulfur loading of the S electrode with good electrochemical performances. The 3D skeleton of MFC can hold massive S/UMC composites and act as a conductive network for the fast transfer of electrons and Li ions. Furthermore, it can serve as an electrolyte reservoir to make a sufficient contact between S and electrolyte, enhancing the utilization of S. With the MFC current collector, the S electrode reaches an areal sulfur loading of 4.2 mg cm and performs a capacity of 839.8 mA h g as well as a capacity retention of 82.5% after 100 cycles. The 3D MFC current collector provides a new insight for the application of Li-S batteries with high areal small sulfur loading and excellent cycle stability.
具有 2600 W h kg 的高能量密度，锂硫（Li-S）电池已被认为是最有前途的储能系统之一。然而，严重的容量衰减，其穿梭效应的结果，阻碍了其商业应用。将小 S 分子封装在微孔碳（UMC）的孔中可以消除溶解的多硫化物，从而完全抑制穿梭效应。然而，由于 UMC 的孔体积有限，S/UMC 的硫负载通常不高于 1mg cm，这对小硫阴极来说是一个巨大的挑战。在本文中，通过应用超轻的 3D 三聚氰胺甲醛基碳泡沫（MFC）作为集流器，我们极大地提高了具有良好电化学性能的 S 电极的面载硫量。MFC 的 3D 骨架可以容纳大量的 S/UMC 复合材料，并作为电子和 Li 离子快速转移的导电网络。此外，它可以作为电解质储库，使 S 与电解质充分接触，提高 S 的利用率。采用 MFC 集流器，S 电极的面载硫量达到 4.2mg cm，容量为 839.8mA h g，经过 100 次循环后容量保持率为 82.5%。3D MFC 集流器为具有高面载硫量和优异循环稳定性的 Li-S 电池的应用提供了新的思路。
