Integrating vertical magnetic fields for safe lithium metal batteries with fast lithium-ion kinetics

The solid-state lithium metal batteries (LMBs) with high energy density and enhanced safety offer significant advantages for the storage of renewable energy. However, the uneven lithium deposition and rapid dendrite formation severely hinder their stable cycling and cause low energy efficiency. Particularly, the poor interfacial contact and short circuits are more likely to occur in high-energy solid-state LMBs, because the used immobile electrolytes that lacks flexibility and adaptability could easily trigger uneven lithium deposition. Herein, we coordinate the external magnetic field within the battery to enhance Li + transfer, fulfilling the modulation of Li + migration direction and uniform distribution of Li + at the battery interface under the guidance of Lorentz forces. With the implementation of enhanced mass transfer by magnetic field, the battery lifespan is extended by 86% compared to the original one. Both experimental and theoretical results verify that the improved stripping/deposition behavior of Li + significantly contributes to the interface stability that is critical for fast charging. Our work sheds light on taming the fundamental electrochemical behavior for long-cycling and high-safety LMBs.