While lithium metal anodes offer unparalleled energy storage potential thanks to their ultra-high capacity (3,860 mAh g⁻¹) and low electrochemical potential (-3.04 V vs. SHE), their "hostless" nature creates significant challenges: dendrite formation, volume expansion, and electrolyte decomposition, hindering practical use.

While strategies such as artificial SEI formation and alloyed hosts offer some mitigation of dendrite growth, they often rely on empirical design and lack a universal framework for optimizing interfacial electric fields and ion dynamics at the atomic level.

Electronegativity – a fundamental property that reflects an atom's ability to attract electrons – has been largely unexplored in the design of lithium-metal battery interfaces. Theoretically, increasing surface electronegativity could enhance Li⁺ adsorption, repel anions, accelerate desolvation, and promote stable nucleation.

To address the above issues, Professor Xi Kai's team from the School of Chemistry at Xi'an Jiaotong University (XJTU) focused on regulating the negative electrode interface and optimizing ion transport in lithium metal batteries, proposing an interface engineering strategy based on electronegativity regulation.

By precisely designing the surface terminal groups of two-dimensional MXene, a high-electronegativity, lithiophilic confined interface was constructed, effectively suppressing space-charge accumulation, achieving a more uniform distribution of Li⁺ flux, and promoting the in-situ formation of a Li2O-rich SEI.

This strategy enabled the lithium negative electrode to maintain a high Coulombic efficiency of 99.41 percent over 1600 cycles and supported the 1 Ah lithium iron phosphate soft-pack battery in achieving a high energy density of 238.06 Wh•kg⁻¹, demonstrating excellent fast charging and cycle stability. 

These research results, titled Accelerating Near-Electrode Li⁺ Transport via High-Electronegativity Substrates for Sustainable Fast-Charging Lithium Metal Batteries, were published in the internationally renowned journal Advanced Functional Materials.