(6bg) Development of Calcium-Based Liquid Metal Batteries for Grid Scale Energy Storage

A liquid metal battery (LMB) is well-positioned to satisfy the demands of large-scale electrochemical energy storage devices due to its ability to obviate classic solid state failure mechanisms and do so with earth abundant materials and easily scalable means of construction. As the negative electrode of LMBs, calcium is an attractive material due to its low electronegativity (consequent high cell voltage) and earth abundance, and its resulting low electrode material costs. However, most researchers have taken Ca off the list for rechargeable batteries due to its high melting temperature and high reactivity combined with its high solubility in molten salt electrolyte, which causes an unacceptably high self-discharge current and poor electrochemical performance. To address these challenges, I initiated a single-electrode study in a three-electrode electrochemical cell to evaluate the electrode performance of Ca-based electrodes including the solubility of Ca into the molten salt. Based on the electrode performance of the single electrode, Ca-based liquid metal batteries were successfully designed.