Modulating Zn²⁺ Desolvation and Deposition with Fluorine-Nitrogen Co-doped Carbon Dot Interlayers for High-Rate Aqueous Zinc-Ion Batteries

The uncontrolled formation of zinc dendrites and detrimental parasitic reactions occurred on the Zn metal anode, particularly under high current densities, critically impeding the practical applications of aqueous zinc-ion batteries (AZIBs). To address these intractable issues, a multifunctional artificial interface is developed through electrospinning technology, comprising polyacrylonitrile (PAN) and fluorine-nitrogen co-doped carbon dots (FN-CDs). This PAN/FN-CD hybrid layer features abundant zincophilic moieties (i.e., ─CHO, ─CN, and ─F) that establish homogeneous nucleation sites for regulated Zn deposition. The dual functionality of zinc affinity and hydrophobicity synergistically lowers the desolvation energy barrier while elevating the Zn²⁺ transference number. Moreover, the 3D fibrous network formed by PAN nanofibers embedded with FN-CDs demonstrates exceptional hydrophobicity, effectively suppressing water-induced Zn corrosion and minimizing electrolyte decomposition. With the unique design strategy, the assembled PAN/FN-CDs-decorated Zn-based symmetric cells exhibit outstanding cycling performance, sustaining operation over 5000 h with minimal overpotential at 1 mA cm⁻² (1 mAh cm⁻²) and more than 3000 h at 10 mA cm⁻² (1 mAh cm⁻²). The corresponding δ-MnO₂ full cell maintained a capacity retention rate of up to 87% after 1500 cycles at 1 A g⁻¹. The work offers fundamental insights into engineering hybrid interfaces with spatially coupled functionalities for dendrite-free AZIBs.