High Capacity Lithium-Sulfur Batteries (> 12 mAh cm^–2) Enabled By 3D-Compact Sulfur Cathode and Polysulfide Adjoining Interface Engineering

Abstract

Beyond the theoretical limitation of current Li-ion batteries technology, there have been large efforts to develop practical next-generation batteries. Among them, lithium-sulfur (Li-S) batteries have been eagerly studied due to their attractive features; the low cost and expected high energy density. To maximize the energy density of Li−S batteries, it is crucial to increase the loading level of sulfur cathode and minimize the electrolyte content. However, excessive amounts of lithium polysulfides (LiPSs) generated in the high loading Li-S batteries limit the stable cycling. In this study, a high-loading S cathode (15 mg cm−2) with a three-dimensional (3D) network structure is fabricated using a simple pelletizing method, and the exhausting overcharging phenomenon, which occurs in the high loading Li−S cell, is successively prevented by pre-treating the lithium metal anode. Moreover, adding a diluent to the electrolyte containing viscous LiPSs enables the facile conversion between S species during the cycling of high loading Li−S cells under lean electrolyte conditions. Finally, a prototype Li−S pouch cell with high energy density (427 Wh kg−1) was realized by combining a compacted 3D cathode with a high-loading, pretreated thin lithium metal and diluent-modified electrolyte. We believe that the results reported herein will be a good guideline to establish proper strategies to achieve high energy density Li−S batteries. Reference s : [1] J.-Y. Hwang, S. Shin, C. S. Yoon, Y.-K. Sun, ACS Energy Lett. 4 (2019) 2787–2795. [2] J.-Y. Hwang, S.-J. Park, C. S. Yoon, Y.-K. Sun, Energy Environ. Sci. 12 (2019) 2174–2784. [3] H. Kim, S. Bang, K.-J. Min, Y.-G. Ham, S.-J. Park and Y.-K. Sun, ACS Appl. Mater. Interfaces 13 (2021) 39435–39445.