Cell design/fabrication and optimization of cell components for rechargeable all-liquid metal batteries

Abstract

Energy storage systems (ESSs) have recently received great attention to store electrical energy genergated from renewable resources such as solar, wind, and waves. Among ESSs, electrochemical energy storage devices (EESDs) such as Li-ion and Na-S batteries have been considered as promising candidates due to its advantages of high energy density and coulombic efficiency. Recently, all-liquid metal batteries (LMBs) have been considered as one of the most powerful EESDs due to their high rate capability, ease of scaling up, long lifespan, and low cost. Neverthelss, researches on cell design and fabricaton of the LMBs have not been fully reported, and this information is critical to testing new materials and identification of their potentials as new anode and cathode materials. In this thesis, the cell components for LMBs were established through circulation from the following three steps: (i) cell design/fabrication, (ii) assembly, and (iii) electrochemical testing. The cell design and its components have been changed and updated after many trials and errors. The cells with compositions of Li|LiCl-LiF|Bi cell was assembled and tested at 50 and 100 mA at 540 oC. It exhibited a relatively long-term cycling at 50 mA. In the updated cell, the Li|LiCl-LiF|Bi cell showed good cycling performance at the current of 100 mA and 200mA at 560 oC. In addition, the Li|LiCl-LiI|Bi-Pb cell demonstrated an excellent long-term cycling stability (>750 cycles (~150 days)) and high coulombic efficiency of >99.3% at 500 mA at 410 oC. Future plans about further optimization of testing cells and development of new chemistries for low-temperature, long-term operation will be discussed