Rahimi Sajad, Lecarme Laureline, Job Nathalie, Alloin Fannie
LEPMI, Grenoble INP, CNRS, Université Savoie Mont Blanc, Université Grenoble Alpes, 38000 Grenoble, France.
Department of Chemical Engineering─NCE (Nanomaterials, Catalysis, Electrochemistry), University of Liège, 4000 Liège, Belgium.
ACS Appl Mater Interfaces. 2025 Jul 2;17(26):38031-38040. doi: 10.1021/acsami.5c05993. Epub 2025 Jun 16.
Despite their promising theoretical performance, lithium-sulfur (Li-S) batteries are often limited by low efficiency, primarily due to the solubility of lithium polysulfides and the low conductivity of sulfur electrodes. Enhancing the incorporation of sulfur into porous carbon with improved polarity could significantly boost the Li-S battery performance. In this study, we doped carbon xerogels with nitrogen atoms and decorated them with iron-based nanostructures using a straightforward and scalable method. The decomposition of nitrogen-containing additives at varying temperatures─specifically 750 °C (FeNC-750) and 950 °C (FeNC-950)─resulted in alterations to the porosity of the xerogel compared to the pristine structure. After impregnating these structures with sulfur to develop the sulfur electrode, we assessed the electrochemical performance of FeNC-750@S and FeNC-950@S, varying the sulfur content and the electrolyte-to-sulfur (E/S) ratio. Our results indicated that the electrochemical performance of the sulfur electrode with high sulfur content was significantly influenced by both the E/S ratio and the porosity of the host materials. Notably, the sulfur electrode with over 80% sulfur content, designated FeNC-950@S, achieved a discharge capacity of 600 mA h g with an E/S ratio of 7.5 mL g and an electrode loading of 3.5 g cm, demonstrating an excellent capacity retention of 96% over 100 cycles at a rate of 0.1 C.
尽管锂硫（Li-S）电池具有令人期待的理论性能，但往往因效率低下而受到限制，这主要是由于多硫化锂的溶解性和硫电极的低导电性。提高硫在具有改善极性的多孔碳中的掺入量，可显著提升锂硫电池的性能。在本研究中，我们使用一种直接且可扩展的方法，用氮原子对碳干凝胶进行掺杂，并以铁基纳米结构对其进行修饰。与原始结构相比，在不同温度（具体为750℃（FeNC-750）和950℃（FeNC-950））下含氮添加剂的分解导致干凝胶的孔隙率发生变化。在用硫浸渍这些结构以制备硫电极后，我们评估了FeNC-750@S和FeNC-950@S的电化学性能，同时改变硫含量和电解液与硫的比例（E/S）。我们的结果表明，高硫含量硫电极的电化学性能受E/S比例和主体材料孔隙率的显著影响。值得注意的是，硫含量超过80%的硫电极（即FeNC-950@S），在E/S比例为7.5 mL g且电极负载为3.5 g cm的情况下，实现了600 mA h g的放电容量，在0.1 C的电流密度下100次循环中展现出96%的出色容量保持率。
