In-situ observation of lithium dendrite growth regulated by the external magnetic field

Lithium (Li) metal-based batteries are anticipated to play a pivotal role in the future evolution of battery technology due to their exceptionally high theoretical capacity. Nevertheless, the unregulated growth of Li dendrites remains a major impediment to their practical utilization. The production of Li dendrites results in a short circuit and a significant reduction in battery life. In this work, the growing state of Li dendrites at different current densities is in-situ observed, and a new strategy for suppressing Li dendrites using a magnetic field is proposed. Under the dual action of magnetic and electric fields, the lithium ion (Li⁺) is acted upon by the Lorentz force and forms a spiral motion. The results show that the Li dendrites are spherically deposited under a magnetic field, eliminating the influence of the tip effect. Moreover, it exhibits excellent cycling stability in Li//Cu cells, and the coulombic efficiency is as a whole up to 93.2 % over 150 cycles. The full-cell assembled with the ternary LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523) cathode exhibits high capacity retention and excellent rate performance. In summary, the innovative strategy of using a magnetic field to inhibit Li dendrite growth, as proposed in this study, holds significant research potential for driving the frontiers of Li metal-based batteries.