Sodium-based batteries are very promising for large-scale applications in near future, thanks to the great abundance and low cost of sodium. Herein, a high-performance liquid metal battery with a negative electrode of metallic sodium is developed. As the metallic sodium has a low melting point (∼ 98°C) and weak corrosion to ceramic seals, the sodium liquid metal batteries (Na-LMBs) offer the merits of low operating temperature, low cost, long lifespan and high safety. However, sodium metal has a high solubility in the electrolyte of single-cationic molten sodium halide mixtures such as NaF-NaCl-NaI due to a high melting point above 500°C, resulting in high self-discharge and low coulombic efficiency. In this work, a multi-cationic ternary molten chloride salt mixture LiCl-NaCl-KCl (59:5:36 mol %) with a melting point lower than 400°C was designed as the electrolyte, which effectively inhibits the dissolution of sodium in the electrolyte. Further, by adopting a dual-active Bi₉Sb alloy positive electrode, the active material utilization was improved. At 100 mA cm⁻², the battery ran stably over 700 cycles at 450°C with a coulombic efficiency of 97%, and active material utilization of about 80%. The battery also exhibited decent rate performance within the current densities of 100-1000 mA cm⁻². The calculation based on a 1 MW/5 MWh demo energy storage plant indicates that the estimated Levelized Cost of Storage (LCOS) of the Na-LMB is lower than 0.029 $/kWh. These results demonstrate the Na-LMB as a promising technology for grid-scale energy storage applications.

由于钠的丰富性和低成本，钠基电池在不久的将来非常有希望大规模应用。在此，开发了一种具有金属钠负极的高性能液态金属电池。由于金属钠具有低熔点（~98°C）和对陶瓷密封件的弱腐蚀，钠液态金属电池（Na-LMBs）具有工作温度低、成本低、寿命长和安全性高等优点。然而，金属钠在单阳离子熔融卤化钠混合物（如 NaF-NaCl-NaI）的电解质中具有高溶解度，因为其熔点高于 500°C，导致自放电高和库仑效率低。在这项工作中，多阳离子三元熔融氯化物盐混合物 LiCl-NaCl-KCl (59:5: 设计了熔点低于400°C的36 mol %)作为电解液，有效抑制了钠在电解液中的溶解。此外，通过采用双主动 Bi₉ Sb合金正极，提高了活性物质利用率。在 100 mA cm ^-2下，电池在 450°C 下稳定运行超过 700 次，库仑效率为 97%，活性材料利用率约为 80%。该电池还在100-1000 mA cm ^-2的电流密度内表现出不错的倍率性能。基于 1 MW/5 MWh 演示储能工厂的计算表明，Na-LMB 的估计平准化储能成本 (LCOS) 低于 0.029 美元/kWh。这些结果表明，Na-LMB 是一种用于电网规模储能应用的有前途的技术。