Nguyen Hung Quoc, Kanedal Mikael Dahl, Todt Juraj, Jin Feng, Do Quyen, Zalka Dora, Maximenko Alexey, Stoian Dragos, Schell Norbert, van Beek Wouter, Fitzek Harald, Rattenberger Johannes, Siller Valerie, Boles Steven T, El Kazzi Mario, Keckes Jozef, Rettenwander Daniel
Department of Materials Science and Engineering, NTNU Norwegian University of Science and Technology, Trondheim 7034, Norway.
Chair of Materials Physics, Montanuniversität Leoben and Erich Schmid Institute for Materials Science, Austrian Academy of Sciences, Leoben 8700, Austria.
J Am Chem Soc. 2025 Jul 9;147(27):23492-23503. doi: 10.1021/jacs.5c00465. Epub 2025 Jun 23.
Room temperature operation of Na-S batteries with liquid electrolytes is plagued by fundamental challenges stemming from polysulfide solubility and their shuttle effects. Inorganic solid electrolytes offer a promising solution by acting as barriers to polysulfide migration, mitigating capacity loss. While the sequential formation of cycling products in molten-electrode and liquid electrolytes-based Na-S batteries generally aligns with the expectations from the Na-S phase diagram, their presence, stability, and transitory behavior in systems with inorganic solid electrolytes at room temperature, remain poorly understood. To address this, we employed operando scanning microbeam X-ray diffraction, operando X-ray photoelectron spectroscopy and ex-situ X-ray absorption spectroscopy to investigate the sulfur conversion mechanisms in Na-S cells with NaPS and Na(BH)(BH) electrolytes. Our findings reveal the formation of crystalline and amorphous polysulfides, including those predicted by the Na-S phase diagram (e.g., NaS, NaS, NaS, NaS), high-order polysulfides observed in liquid-electrolyte systems (e.g., NaS, where = 6-8), and phases like NaS typically stable only under high-temperature or high-pressure conditions. We demonstrate that these transitions are governed by diffusion-limited kinetics and localized stress concentrations, emphasizing the critical role of pressure, which serves as both a thermodynamic variable, as well as a design parameter, for optimizing solid-state Na-S battery performance necessary for pushing these cells closer to the commercial frontier.
使用液体电解质的钠硫电池在室温下运行面临着多硫化物溶解性及其穿梭效应带来的根本性挑战。无机固体电解质通过充当多硫化物迁移的屏障，减轻容量损失，提供了一种有前景的解决方案。虽然基于熔融电极和液体电解质的钠硫电池中循环产物的顺序形成通常与钠硫相图的预期一致，但它们在室温下无机固体电解质系统中的存在、稳定性和瞬态行为仍知之甚少。为了解决这个问题，我们采用了原位扫描微束X射线衍射、原位X射线光电子能谱和非原位X射线吸收光谱来研究使用NaPS和Na(BH)(BH)电解质的钠硫电池中的硫转化机制。我们的研究结果揭示了结晶和非晶态多硫化物的形成，包括钠硫相图预测的那些（例如，NaS、NaS、NaS、NaS）、在液体电解质系统中观察到的高阶多硫化物（例如，NaS，其中 = 6 - 8）以及通常仅在高温或高压条件下稳定的NaS等相。我们证明这些转变受扩散限制动力学和局部应力集中控制，强调了压力的关键作用，压力既是一个热力学变量，也是一个设计参数，对于优化固态钠硫电池性能至关重要，这有助于使这些电池更接近商业前沿。
