Designing secure and reliable large scale energy storage systems is extremely important to make efficient use of renewable energy as well as to reduce reliance on non-renewable fossil fuels. Among energy storage technologies, sodium (Na)-beta alumina batteries (NBBs) have gained significant attention due to long cycle life, high energy density, and superior safety. However, there have been challenges that obstacle their practical use, such as high operating temperatures and expensive cathode materials.

Two NBB chemistries, such as sodium-sulfur (Na-S) battery and sodium metal halide (Na-MH) battery, have been extensively studied in the past. In this study, we introduce a novel concept of Na-metal battery using low-cost and earth-abundant metals in a planar cell configuration. The novel battery system is operated at a temperature below 170°C to maintain the electrode materials in a liquid state, which is much lower than the reported temperatures applied for the conventional NBB technologies. Various galvanostatic tests were conducted to investigate the optimized conditions.

Due to the lower operating temperature, the use of inexpensive cathode materials and high energy efficiency, our “Non ZEBRA-type” Na-metal system can offer further cost reduction, high safety, and reliability for future energy storage systems.