Electrostatic self-assembled aminated dendritic silica/lithium polyacrylate artificial interphase for long-life Li...

The unstable solid electrolyte interphase (SEI) on lithium metal anodes and problematic dendrite growth critically impede the commercialization of lithium metal batteries (LMBs). Although various organic-inorganic hybrid SEI have been explored, achieving a simultaneously robust and ion-conductive interface remains challenging due to the intrinsic trade-off between mechanical rigidity and electrochemical kinetics. Herein, an artificial composite SEI comprising aminated dendritic mesoporous silica (NH₂-DMS) and lithium polyacrylate (PAALi) was constructed via an electrostatic self-assembly strategy to address these issues. Distinct from conventional hybrid coatings, electrostatic interactions between amino groups (-NH₂) and carboxylate anions (-COO^-) enable homogeneous hybrid integration and enhanced interfacial stability. Structurally, the rigid NH₂-DMS framework provides three-dimensionally interconnected ion-transport channels that homogenize lithium-ion (Li⁺) flux, while the flexible PAALi chains establish dynamic coordination between -COO^- and Li⁺, facilitating rapid ion transport and accommodating interfacial fluctuations. Meanwhile, the negatively charged -COO^- groups regulate interfacial ion distribution by suppressing excessive anion accumulation, thereby reducing polarization and increasing the Li⁺ transference number (t_Li⁺) to 0.81. Benefiting from the synergistic integration of mechanical reinforcement, fast ion transport, and interfacial charge regulation, the artificial SEI enables dendrite-free lithium deposition and long-term cycling stability exceeding 2000 h at a high current density of 5 mA cm^-2.Consequently, the synergistic combination of NH₂-DMS and PAALi in the composite SEI layer enables stable and dendrite-free LMBs.