Breaking the interfacial stability bottleneck of Zn anode via biomass carbon dots-enabled endogenous hybrid...

Aqueous zinc-ion batteries (AZIBs) are promising for grid-scale energy storage but are hindered by Zn anode instability, including dendrite growth, hydrogen evolution, and corrosion. Existing strategies often fail to address all three issues simultaneously using sustainable materials. Here, this trade-off is broken by a green electrolyte additive derived from waste Osmanthus fragrans leaves, namely N/S self-doped carbon dots, which enables the in-situ construction of a robust endogenous organic-inorganic hybrid interphase (EHI) on the Zn anode. The resulting EHI comprises inorganic ZnS/ZnO/ZnN_x nanodomains and an N/O/S-rich organic framework, achieving synergistic bifunctional regulation of Zn deposition behavior and interfacial electrolyte chemistry. Specifically, the inorganic nanodomains homogenize Zn²⁺ flux and modulate the nucleation overpotential, promoting compact Zn deposition. Meanwhile, the organic components, featuring electron-deficient C=O/S=O groups and multidentate C-N/C-S ligands, synergistically accelerate de-solvation through hydrogen-bonding interactions to reduce active water molecules and selective chelation of Zn²⁺, thereby simultaneously suppressing hydrogen evolution, lowering interfacial polarization, and guiding uniform Zn deposition. In an optimized electrolyte, the Zn||Zn symmetric cell achieves exceptional long-term cycling stability (7440 h at 1 mA cm^-2 and 6000 h at 5 mA cm^-2). Moreover, the Zn||Cu half-cell achieves a maximum Coulombic efficiency of 99.85%, and full cells show superior rate capability and cycling stability. This work provides a new paradigm for designing high-performance zinc batteries and promoting green development.