Regulating Interfacial Dynamic Self-Adjusting Hydrophobic Layer via Cationic Molecular Structure for Ultra-Stable...

The structure of solution additives significantly affects the polarization and dendrite behavior of metal batteries. In this study, we propose, for the first time, the "hydrophilic-lipophilic balance (HLB) value-spatial configuration synergistic regulation" strategy by selecting cations with different structures as additives, successfully revealing the structure-activity relationship between additive structures and the stability of the anode interface adsorption layer. Among them, the butyltrimethylammonium chloride additive (ADD4), which has a low HLB value and a linear structure, exhibits the most stable interfacial structure. The stable hydrophobic region formed by its spontaneous aggregation and assembly shows a repulsive effect on hydrated protons. The constructed protective layer can effectively reduce overpotential and inhibit the formation of by-products. The battery with ADD4 exhibits excellent stability, with over 1700 cycles and an average Coulombic efficiency of 99.7%. The full laboratory cells and pouch cells can also maintain very good cyclability, verifying their feasibility for practical applications. This study emphasizes that exploring the relationship between the hydrophilic-hydrophobic properties, microstructure of additive ions, and the stability of the adsorption layer is crucial for designing appropriate electrolyte-electrode interface layers.