Regulating the discharge performance and electrode interface of liquid metal batteries through external magnetic fields

Liquid metal batteries (LMBs) are promising for large-scale energy storage due to long cycle life, high safety, and low cost. However, LMBs suffer from large concentration polarization during discharge process and a certain risk of internal short-circuit, which severely hinders their practical application. In this work, we propose the strategy of applying external magnetic fields to address these two issues. Firstly, a numerical model and logical reasoning are employed to explain why external magnetic fields are effective. Furthermore, experimental results demonstrate that external magnetic fields significantly enhance the discharge performance of LMBs. At a current density of 500 mA cm−2, a 61.9 mT magnetic field increases the discharge voltage by 34.64 %. At 1000 mA cm−2, a 29.6 mT magnetic field raises the discharge voltage by 74.5 %. Moreover, external magnetic fields can quickly restore the short-circuited LMBs, and the charge-discharge performance can be completely recover to the pre-short-circuit state. This study provides novel insights into improving electrochemical performance and restructuring electrode interfaces through external magnetic fields.