Joint Center for Energy Storage Research (JCESR), Pacific Northwest National Laboratory , Richland, Washington 99352, United States.
Joint Center for Energy Storage Research (JCESR), Sandia National Laboratories , Albuquerque, New Mexico 87185, United States.
Nano Lett. 2017 May 10;17(5):3061-3067. doi: 10.1021/acs.nanolett.7b00417. Epub 2017 May 1.
Li-S batteries have been extensively studied using rigid carbon as the host for sulfur encapsulation, but improving the properties with a reduced electrolyte amount remains a significant challenge. This is critical for achieving high energy density. Here, we developed a soft PEOLiTFSI polymer swellable gel as a nanoscale reservoir to trap the polysulfides under lean electrolyte conditions. The PEOLiTFSI gel immobilizes the electrolyte and confines polysulfides within the ion conducting phase. The Li-S cell with a much lower electrolyte to sulfur ratio (E/S) of 4 g/g (3.3 mL/g) could deliver a capacity of 1200 mA h/g, 4.6 mA h/cm, and good cycle life. The accumulation of polysulfide reduction products, such as LiS, on the cathode, is identified as the potential mechanism for capacity fading under lean electrolyte conditions.
锂-硫电池已经被广泛研究，使用刚性碳作为硫封装的主体，但在减少电解质用量的情况下改善性能仍然是一个重大挑战。这对于实现高能量密度至关重要。在这里，我们开发了一种柔软的聚环氧乙烷锂双三氟甲磺酰亚胺聚合物溶胀凝胶作为纳米级储库，在贫电解质条件下捕获多硫化物。PEOLiTFSI 凝胶固定电解质并将多硫化物限制在离子传导相内。在电解质与硫的比例（E/S）低至 4 g/g（3.3 mL/g）的情况下，Li-S 电池的容量可以达到 1200 mA h/g、4.6 mA h/cm，并且具有良好的循环寿命。在贫电解质条件下，容量衰减的潜在机制被认为是多硫化物还原产物，如 LiS，在阴极上积累。
