Enhancing Energy Conversion Efficiency and Suppression of Side Reactions in Li-O 2 Batteries through a Magnetic Field Strategy

Enhancing the energy conversion efficiency of lithium-oxygen batteries remains a significant challenge. Side reactions and slow transfers of Li⁺, O₂, and electrons cause the accumulation of insoluble byproducts on the cathode, leading to high discharge overpotentials and limited reversibility. In this study, the authors introduce a magnetic field to address these issues. Applying an external magnetic field to ferromagnetic catalysts significantly reduces the overpotential to only 0.57 V at 200 mA/g, while maintaining exceptional rate performance and cycle stability. In-situ characterization experiments demonstrate effective suppression of byproducts, primarily Li₂CO₃. Theoretical calculations further reveal that the magnetic field stabilizes highly reactive singlet oxygen within the battery system, inhibiting the byproduct formation pathways. Furthermore, the magnetic field plays a crucial role in promoting the decomposition of discharge products and Li⁺ mass transfer. Together, these effects minimize polarization and improve energy transfer efficiency, offering a versatile strategy for advanced metal-air batteries.