The poor stability and slow lithium ion (Li+) transfer kinetics of solid electrolyte interphase (SEI) pose significant challenges to lithium (Li) metal batteries. Although various SEI-related strategies have been developed, the Li+ transport properties and uniform Li deposition still require substantial improvement for fast-charging applications. Herein, we introduce a dielectric, single-ion-conductive artificial SEI (DS-SEI) composed of lithiated Nafion and BaTiO3 (BTO) nanoceramics to address these issues. The lithiated Nafion stabilizes the Li anode with its elastic F-rich components and facilitates fast, single Li+ conduction through its anion-anchored structure. The high-dielectric BTO dynamically homogenizes the electric field (E-field) to promote uniform Li deposition, synergistically enhancing intrinsic single Li+ conductivity and Li+ desolvation/diffusion kinetics, thereby enabling fast charging of the Li anode. Consequently, the DS-SEI protected Li anode can cycle over 6800 h in a Li||Li cell at 10 mA cm-2/5 mAh cm-2, over 400 cycles in a 2.75 mAh cm-2 Li||LiFePO4 cell at 1C, with 83.0 % capacity retention at 6C (16.5 mA cm-2), and maintain stable cycling in a 5.62 mAh cm-2 Li||Li6PS5Cl|| LiNi0.8Co0.1Mn0.1O2 all solid-state cell. Our findings provide insights into the interfacial regulation of Li anode, paving the way for fast-charging Li metal batteries.
Keywords: Dielectric; Lithium metal anode; Single ion conduction; Solid electrolyte interphase.
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