Synergistic Regulation of Li-Ion Transport and Crystallographic Orientation via Lanthanum Iodide for High-Performance Lithium Metal Anodes

Abstract

Research on lithium metal anodes confronts critical challenges from uncontrolled dendrite growth and unstable SEIs, especially under high-energy conditions. Here, we report a surface engineering strategy utilizing lanthanum triiodide (LaI₃) to regulate Li-ion transport dynamics and lithium crystal growth kinetics. LaI₃ reacts with Li to form metallic La and LiI, creating a surface modification layer in inorganic components, which enhances interfacial stability and enables stable cycling of the Li anode. Further experiments and calculations show that the La/LiI-rich inorganic SEI layer regulates Li deposition orientation and improves interfacial transport kinetics. Specifically, La doping elevates the s-band center of the Li (200) facet, minimizing the s-band center energy difference and promoting the preferred orientation and planar growth of Li deposition. Meanwhile, LiI-rich SEI exhibits an ultralow Li⁺ migration barrier (0.035 eV) and superior Li⁺ adsorption, enabling rapid ion transport and uniform deposition. The synergistic effects are manifested in practical 5.93 Ah Li||NCM90 pouch cells, achieving a high energy density of 500.93 Wh kg^–1 and maintaining 86.8% capacity retention after 50 cycles with an average Coulombic efficiency of 99.47%. This work presents a scalable approach for high-energy lithium metal batteries by combining simultaneous crystallographic orientation control and SEI engineering through interfacial chemistry manipulation.