He Jiarui, Bhargav Amruth, Shin Woochul, Manthiram Arumugam
Materials Science and Engineering Program & Texas Materials Institute, The University of Texas at Austin, Austin, Texas 78712, United States.
J Am Chem Soc. 2021 Dec 8;143(48):20241-20248. doi: 10.1021/jacs.1c08851. Epub 2021 Nov 24.
Ambient-temperature sodium-sulfur batteries are an appealing, sustainable, and low-cost alternative to lithium-ion batteries due to their high material abundance and specific energy of 1274 W h kg. However, their viability is hampered by Na polysulfide (NaPS) shuttling, Na loss due to side reactions with the electrolyte, and dendrite formation. Here, we demonstrate that a solid-electrolyte interphase rich in inorganic components can be realized at both the sulfur cathode and the Na anode by tweaking the solvation structure of the electrolyte. This transforms the sulfur redox process from conventional dissolution-precipitation chemistry into a quasi-solid-state reaction, which eliminates NaPS shuttling and facilitates dendrite-free Na-metal plating and stripping. With the solvated ionic liquid electrolyte structure, a high initial capacity of 922 mA h g with a capacity fade of as low as 0.10% per cycle over 300 cycles was achieved. The scalability of this approach to pouch cells with practically necessary parameters demonstrates its potential for practical viability.
常温钠硫电池因其材料丰富度高且比能量达1274瓦时/千克，是一种有吸引力、可持续且低成本的锂离子电池替代品。然而，多硫化钠（NaPS）穿梭、与电解质发生副反应导致的钠损失以及枝晶形成阻碍了它们的可行性。在此，我们证明通过调整电解质的溶剂化结构，可在硫正极和钠负极处实现富含无机成分的固体电解质界面。这将硫氧化还原过程从传统的溶解 - 沉淀化学转变为准固态反应，消除了NaPS穿梭，并促进无枝晶的钠金属电镀和剥离。采用溶剂化离子液体电解质结构，实现了922毫安时/克的高初始容量，在300次循环中容量衰减低至每循环0.10%。这种方法对具有实际所需参数的软包电池的可扩展性证明了其实际可行性的潜力。
