Sul Hyunki, Lee Dongsoo, Manthiram Arumugam
Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
Small. 2024 Aug;20(31):e2400728. doi: 10.1002/smll.202400728. Epub 2024 Mar 3.
Lithium-sulfur (Li-S) batteries, with their high energy density, nontoxicity, and the natural abundance of sulfur, hold immense potential as the next-generation energy storage technology. To maximize the actual energy density of the Li-S batteries for practical applications, it is crucial to escalate the areal capacity of the sulfur cathode by fabricating an electrode with high sulfur loading. Herein, ultra-high sulfur loading (up to 12 mg cm) cathodes are fabricated through an industrially viable and sustainable solvent-free dry-processing method that utilizes a polytetrafluoroethylene binder fibrillation. Due to its low porosity cathode architecture formed by the binder fibrillation process, the dry-processed electrodes exhibit a relatively lower initial capacity compared to the slurry-processed electrode. However, its mechanical stability is well maintained throughout the cycling without the formation of electrode cracking, demonstrating significantly superior cycling stability. Additionally, through the optimization of the dry-processing, a single-layer pouch cell with a loading of 9 mg cm and a novel multi-layer pouch cell that uses an aluminum mesh as its current collector with a total loading of 14 mg cm are introduced. To address the reduced initial capacity of dry-processed electrodes, strategies such as incorporating electrocatalysts or employing prelithiated active materials are suggested.
锂硫（Li-S）电池具有高能量密度、无毒以及硫储量丰富等特点，作为下一代储能技术具有巨大潜力。为了在实际应用中最大化Li-S电池的实际能量密度，通过制造高硫负载的电极来提高硫正极的面积容量至关重要。在此，通过一种工业上可行且可持续的无溶剂干法工艺制造出超高硫负载（高达12 mg/cm²）的正极，该工艺利用聚四氟乙烯粘合剂原纤化。由于粘合剂原纤化过程形成的低孔隙率正极结构，与浆料法制备的电极相比，干法制备的电极初始容量相对较低。然而，在整个循环过程中其机械稳定性得到良好维持，未形成电极开裂，展现出显著优越的循环稳定性。此外，通过干法工艺的优化，引入了负载为9 mg/cm²的单层软包电池以及使用铝网作为集流体、总负载为14 mg/cm²的新型多层软包电池。为了解决干法制备电极初始容量降低的问题，提出了诸如加入电催化剂或采用预锂化活性材料等策略。
