Effects of directional magnetic field on the performance and degradation of lithium-ion batteries

Lithium-ion batteries are widely used in various applications such as electric vehicles and energy storage systems owing to their high energy density and excellent stability. Accordingly, various studies are actively underway to improve battery life and suppress degradation; however, most have focused on advancing internal materials such as cathodes, anodes, and electrolytes. This approach has limitations, including complex manufacturing processes, increased costs, and difficulty in applying such changes to existing systems in operation. In this study, we propose an external, nonintrusive approach involving the application of an external magnetic field to a battery to overcome these limitations. This method can improve performance through physical stimulation without altering the internal structure of the cell, making it easily applicable to commercial systems. First, we compared the electrochemical characteristics based on the magnetic polarity using a beaker cell. Subsequently, the optimal conditions to a commercial 18,650 lithium-ion battery were applied to analyze and compare the charge/discharge cycle performance with and without application of magnetic field. Additionally, we conducted electrochemical impedance spectroscopy, electrode surface observations, and X-ray photoelectron spectroscopy of the cells after cycling to comprehensively evaluate the effect of the magnetic field on battery degradation. This study demonstrates the feasibility of improving battery life through a simple and practical approach of applying an external magnetic field, and highlights its potential as an alternative technique to enhance the performance of existing battery systems. • External magnetic fields suppress lithium-ion degradation and improve cycle life. • Beaker-cell EIS found an axial ring magnet with the lowest internal resistance. • Ring(S) and Ring(N) configurations were tested on 18,650 cells for 200 cycles. • Compared with Bare, Ring(S) most improved SOH, efficiency, etc. • MHD/Lorentz-force analysis confirmed that Ring(N) best suppresses degradation.