Charge regulation by ferromagnetic metal/LiF spin‐polarized interface for high‐performance Li metal anodes

Abstract The interfacial characteristics of the Li metal anode (LMA) play a crucial role in its overall performance. Despite various materials being applied to modify the interface, a comprehensive understanding of their specific mechanisms remains to be investigated. Herein, we have prepared carbon cloth (CC) frameworks with their surfaces modified using ferromagnetic metal/LiF heterogeneous films (T M ‐LiF‐CC) as the substrate for LMA, which exhibit superior electrochemical performance. Utilizing ferromagnetic Co as a representative example, our study demonstrates that the enhanced performance of Co‐LiF‐CC, compared to bare CC, is attributed to the spin‐polarized interface contributed by the Co/LiF heterostructure. Co and LiF play individual roles in redistributing electrons and Li + to promote homogeneous Li deposition. Co nanoparticles play a crucial role in generating strong surface capacitance by storing electrons in spin‐split bands, while LiF, with low surface diffusion barriers, ensures fast transportation of Li + . The Co‐LiF‐CC@Li electrodes deliver long lives of 7400 and 3600 h at 1 and 2 mA·cm −2 in symmetric cells, respectively; moreover, they enable full batteries with high and durable capacities, particularly when the N/P ratios are low (3.3 or even 1.7).