Enhancing capacity utilization of Li|LiCl-KCl-CsCl|Bi (300 °C) liquid metal batteries through the application of external magnetic fields

Long-cycle-life, high-safety liquid metal batteries (LMBs) are considered competitive alternatives for large-scale energy storage applications. LMBs typically operate at high temperatures, and reducing their operating temperature has been a focus of research. In this study, we adopt a multi-cation molten salt LiCl-KCl-CsCl as the electrolyte for LMBs and achieve the stable operation of Li|LiCl-KCl-CsCl|Bi battery at 300 degrees C for the first time. However, the lower operating temperature significantly deteriorates the kinetic performance, resulting in a capacity utilization of only about 30 %. To address this issue, we apply a certain intensity of magnetic field to the battery using Helmholtz coils, which increases the capacity utilization to 100 %. This study combines the strategy of low-temperature LMBs with external magnetic field regulation, not only achieving a low operating temperature but also ensuring complete capacity release. Furthermore, this approach paves the way for the potential use of permanent magnets within battery modules to provide the magnetic field environment, without the risk of demagnetization.