Hojong Kim

Magnesium−Antimony Liquid Metal Battery for Stationary Energy Storage

Batteries are an attractive option for grid-scale energy storage applications because of their small footprint and flexible siting. A high-temperature (700 °C) magnesium-antimony (Mg||Sb) liquid metal battery comprising a negative electrode of Mg, a molten salt electrolyte (MgCl(2)-KCl-NaCl), and a positive electrode of Sb is proposed and characterized. Because of the immiscibility of the contiguous salt and metal phases, they stratify by density into three distinct layers. Cells were cycled at rates ranging from 50 to 200 mA/cm(2) and demonstrated up to 69% DC-DC energy efficiency. The self-segregating nature of the battery components and the use of low-cost materials results in a promising technology for stationary energy storage applications.

Electrolysis of Molten Iron Oxide with an Iridium Anode: The Role of Electrolyte Basicity

Molten oxide electrolysis (MOE) is a carbon-free, electrochemical technique to decompose a metal oxide directly into liquid metal and oxygen gas. From an environmental perspective what makes MOE attractive is its ability to extract metal without generating greenhouse gases. Hence, an inert anode capable of sustained oxygen evolution is a critical enabling component for the technology. To this end, iridium has been evaluated in ironmaking cells operated with two different electrolytes. The basicity of the electrolyte has been found to have a dramatic effect on the stability of the iridium anode. The rate of iridium loss in an acidic melt with high silica content has been measured to be much less than that in a basic melt with high calcia content.

Calcium-based multi-element chemistry for grid-scale electrochemical energy storage.

Calcium is an attractive material for the negative electrode in a rechargeable battery due to its low electronegativity (high cell voltage), double valence, earth abundance and low cost; however, the use of calcium has historically eluded researchers due to its high melting temperature, high reactivity and unfavorably high solubility in molten salts. Here we demonstrate a long-cycle-life calcium-metal-based rechargeable battery for grid-scale energy storage. By deploying a multi-cation binary electrolyte in concert with an alloyed negative electrode, calcium solubility in the electrolyte is suppressed and operating temperature is reduced. These chemical mitigation strategies also engage another element in energy storage reactions resulting in a multi-element battery. These initial results demonstrate how the synergistic effects of deploying multiple chemical mitigation strategies coupled with the relaxation of the requirement of a single itinerant ion can unlock calcium-based chemistries and produce a battery with enhanced performance.

Stress Corrosion Cracking of Alloy 625 in pH 2 Aqueous Solution at High Temperature and Pressure

Abstract Stress corrosion cracking (SCC) of Alloy 625 (UNS N06625) has been investigated in pH 2 aqueous solution at high temperatures (300°C to 426°C) and high pressure (24.1 MPa) to understand th...

Rare Metal Technology 2015

The Search Minerals Foxtrot project in Labrador is a surface deposit enriched in the highly sought after heavy rare earth elements. Early metallurgical work investigated beneficiation of the rare earth content of the Foxtrot resource using flotation, gravity separation and magnetic separation. The concentrate was then processed by acid baking and water leaching to produce a REE leachate for purification and recovery. The Search Minerals Direct Extraction Process was developed through bypassing the beneficiation process and directly acid treating a coarse crushed ore material prior to water leaching. The result is a simple, low risk technical process for direct recovery. Concurrently, the treatment of the water leach solution was modified to produce a high grade (98.9% total rare earth oxide) product for refining.