Sulfonated polydopamine–engineered SWCNT hosts with guided Ag nucleation for stabilized lithium metal anodes

Abstract

Lithium metal anodes suffer from unstable Li nucleation, dendritic growth, and interfacial instability. Here, we report a molecularly engineered three-dimensional host composed of sulfonated polydopamine–modified single-walled carbon nanotubes (SPDA@SWCNTs) incorporating Ag nanoparticles. Sulfonation moderates dopamine polymerization, thereby forming a thin, conformal SPDA layer that improves SWCNT dispersion, enhances network uniformity, and increases electrolyte wettability. Catechol/quinone-mediated in situ reduction generates ∼6 nm Ag nanoparticles that assemble into 10–27 nm features and serve as lithiophilic nucleation sites. The resulting Ag@SPDA@SWCNT host exhibits a reduced Li nucleation overpotential (17 mV) and improved Coulombic efficiency (95.9%) in half cells, together with compact Li deposition at an areal capacity of 5 mAh cm−2. In symmetric cells, stable cycling is maintained for over 750 h with a polarization of approximately 15 mV, accompanied by relatively low SEI and charge-transfer resistances. When paired with NCM811 cathodes, the full cell achieves 87.46% capacity retention at 50 cycles and 56.73% after 100 cycles, with an average CE of 98.9%. These results suggest that integrating tailored surface chemistry with lithiophilic nanoparticle incorporation provides an effective approach for improving Li nucleation behavior and interfacial stability in lithium metal anodes.