Accelerating Near-Electrode Li⁺ Transport via High-Electronegativity Substrates for Sustainable Fast-Charging Lithium Metal Batteries

Electronegativity engineering offers a powerful yet underexplored paradigm for regulating interfacial ion transport in rechargeable lithium metal batteries (LMBs), where uncontrolled dendrite growth and unstable solid electrolyte interphases (SEIs) remain critical bottlenecks for fast-charging and high-energy applications. Here, an oxygen-functionalized MXene (Ti₃C₂O_x) scaffold with expanded interlayer spacing and high surface electronegativity, enabling cationophilic confinement of Li⁺ flux, is demonstrated. Density functional theory calculations and finite element simulations reveal that electronegative oxygen terminations induce a uniform interfacial Li⁺ concentration field, reduce nucleation overpotential, and promote the in situ formation of a Li₂O-rich SEI with superior Li⁺ conductivity. This architecture delivers a Coulombic efficiency of 99.41% over 1600 cycles and sustains 1600 h of stable operation in symmetric cells with an ultralow overpotential of 11 mV. Practical full-cell tests confirm its robustness, with a 1 Ah Ti₃C₂O_x@Li||LiFePO₄ pouch cell achieving an energy density of 238.06 Wh kg⁻¹ at an electrolyte-to-capacity ratio of 2.5 g Ah⁻¹ while retaining 93.72% of its capacity after 40 cycles. Beyond a material advance, this work establishes electronegativity-tailored interfacial engineering as a universal design principle to harmonize electrochemical kinetics and mass transport, paving the way for dendrite-free, high-rate, and high-loading lithium metal anodes.