Rapid-charging aluminium-sulfur batteries operated at 85 °C with a quaternary molten salt electrolyte

• Published in: Nature communications 2024-01, Vol.15 (1), p.596-596, Article 596
• Main Authors: Meng, Jiashen, Hong, Xufeng, Xiao, Zhitong, Xu, Linhan, Zhu, Lujun, Jia, Yongfeng, Liu, Fang, Mai, Liqiang, Pang, Quanquan
• Format: Article
• Language: English
• Subjects: 119/118; 140/133; 140/146; 147/135; 147/143; 639/301/299/891; 639/4077/4079/891; Absorption spectroscopy; Aluminum; Batteries; Charging; Electrolytes; Energy storage; High temperature; Humanities and Social Sciences; Intermediates; Melting point; Melting points; Molten salt electrolytes; Molten salts; multidisciplinary; Operating temperature; Reaction kinetics; Reaction mechanisms; Salts; Science; Science & Technology - Other Topics; Science (multidisciplinary); Sulfur; Sustainable materials; Thermal management; X ray absorption; X-ray absorption spectroscopy
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-44691-8

Molten salt aluminum-sulfur batteries are based exclusively on resourcefully sustainable materials, and are promising for large-scale energy storage owed to their high-rate capability and moderate energy density; but the operating temperature is still high, prohibiting their applications. Here we report a rapid-charging aluminium-sulfur battery operated at a sub-water-boiling temperature of 85 °C with a tamed quaternary molten salt electrolyte. The quaternary alkali chloroaluminate melt – possessing abundant electrochemically active high-order Al-Cl clusters and yet exhibiting a low melting point – facilitates fast Al 3+ desolvation. A nitrogen-functionalized porous carbon further mediates the sulfur reaction, enabling the battery with rapid-charging capability and excellent cycling stability with 85.4% capacity retention over 1400 cycles at a charging rate of 1 C. Importantly, we demonstrate that the asymmetric sulfur reaction mechanism that involves formation of polysulfide intermediates, as revealed by operando X-ray absorption spectroscopy, accounts for the high reaction kinetics at such temperature wherein the thermal management can be greatly simplified by using water as the heating media. Molten salt aluminium-sulfur batteries exhibit high-rate capability and moderate energy density, but suffer from high operating temperature. Here the authors demonstrate a rapidly charging aluminum-sulfur battery operating at 85 °C enabled by a quaternary alkali chloroaluminate electrolyte.