Intermediate Temperature Na-ZnCl2 Battery

Abstract

Sodium-metal halide (Na-MH) batteries have been considered as one of the most attractive energy storage systems for stationary applications. Significant progress has been achieved in the Na-MH technologies during the past a few of decades. However, the batteries are still facing challenges in battery performance and cost. Recently, we have been working on advanced planar type Na-MH batteries with operating temperatures below 200oC. It was found that the low-temperature operation dramatically improved the battery performance (e.g., cycle life). Meanwhile, we have put efforts to replace the major cathode component of Ni in the Na-NiCl2 chemistry with Zn, which potentially can cut down around 46 and 20% of the cell material and overall battery costs. In this study, we further investigated the performance of the Na-ZnCl2 battery at intermediate-temperatures (e.g., 190oC). It was found the Na-ZnCl2 chemistry has significant higher rate capability over the Na-NiCl2 counterpart under similar operating conditions. The mechanisms for the higher rate capability could be related to the improved mass or charge transfer rate in the Na-ZnCl2 cathode. We believe this high-performance, low-cost, and safe Na-ZnCl2 battery will bring it one-step closer for broad market penetration of the Na-MH technologies. Figure 1