Origin of Solid Electrolyte Interphase Heterogeneity on Lithium Metal Anodes and Its Mitigation with Electrolyte Additives
Aoxuan Wang, Ting Yang, Linxue Zhang, Changdong Li, Hao Chen, Yumeng Zhao, Jiayan Luo
Abstract
Lithium metal anode (LMA) stands as a promising candidate for next-generation high-energy-density batteries, yet its viability is critically compromised by heterogeneous solid electrolyte interphase (SEI) formation. This interfacial inhomogeneity manifested as spatially fluctuating Li + transport kinetics provokes erratic lithium deposition and dendrite propagation. Here, we reveal that current strategies to homogenize SEI are impeded by an overlooked origin: crystallographic anisotropy-driven adsorption bias of electrolyte components across polycrystalline Li (poly-Li) surfaces, thereby dictating SEI heterogeneity. We further decouple the correlation between lattice orientation and adsorption energetics by engineering a dual-additive electrolyte [fluoroethylene carbonate (FEC) and propane sultone (PS)]. These additives establish plane adsorption uniformity, forming a homogeneous SEI that spatially synchronizes Li + flux. When paired with a high-loading LiCoO 2 cathode (3.86 mAh cm –2 ), the stabilized anode enables 80% capacity retention over 380 cycles under ultralean conditions (N/P = 2.30, E/C = 2.34 g Ah –1 ), tripling the cycle life versus conventional electrolytes while suppressing dendritic failure modes.