Despite its promise as a safe, reliable system for grid-scale electrical energy storage, traditional molten sodium (Na) battery deployment remains limited by cost-inflating high-temperature operation. Here, we describe a high-performance sodium iodide-gallium chloride (NaI-GaCl₃) molten salt catholyte that enables a dramatic reduction in molten Na battery operating temperature from near 300°C to 110°C. We demonstrate stable, high-performance electrochemical cycling in a high-voltage (3.65 V) Na-NaI battery for >8 months at 110°C. Supporting this demonstration, characterization of the catholyte physical and electrochemical properties identifies critical composition, voltage, and state of charge boundaries associated with this enabling inorganic molten salt electrolyte. Symmetric and full cell testing show that the catholyte salt can support practical current densities in a low-temperature system. Collectively, these studies describe the critical catholyte properties that may lead to the realization of a new class of low-temperature molten Na batteries.

尽管它有望成为用于电网规模电能存储的安全、可靠的系统，但传统的熔融钠 (Na) 电池部署仍然受到成本膨胀的高温操作的限制。在这里，我们描述了一种高性能碘化钠 - 氯化镓 (NaI-GaCl ₃) 熔融盐阴极电解液，可将熔融钠电池的工作温度从接近 300°C 大幅降低至 110°C。我们展示了在高压 (3.65 V) Na-NaI 电池中在 110°C 下稳定、高性能的电化学循环超过 8 个月。为支持这一演示，阴极电解液物理和电化学特性的表征确定了与这种使无机熔盐电解质相关的关键成分、电压和电荷边界状态。对称和全电池测试表明，阴极电解盐可以支持低温系统中的实际电流密度。总的来说，这些研究描述了可能导致实现新型低温熔融钠电池的关键阴极电解液特性。