Nitrogen/Fluorine Co‐Doped Carbon Dots as an Electrolyte Additive to Stabilize the Zinc Anode

Abstract The inherent limitations of zinc anodes constrain the performance of zinc‐ion batteries (ZIBs). Viable electrolyte additives offer a practical approach for stabilizing the zinc anode interfaces. This work systematically investigates the role of nitrogen/fluorine co‐doped carbon dots (NF‐CDs) as an electrolyte additive. Theoretical investigations indicate that the nitrogen and fluorine atoms on NF‐CDs have stronger binding energies with Zn 2+ than water molecules and Zn 2+ , enabling NF‐CDs to partially replace coordinated water within the Zn 2+ solvation sheath and reconstruct the Zn 2+ solvation structure. This mechanism is corroborated by nuclear magnetic resonance and Fourier transform infrared spectroscopy. The reconfigured solvation structure weakens the coordination between the bound water and Zn 2+ , inhibiting water‐induced side reactions and enhancing the electrode's electrochemical stability. Concurrently, NF‐CDs’ steric hindrance contributes to interfacial stabilization, facilitates the diffusion of solvated Zn 2+ , and mitigates zinc aggregation. Consequently, the zinc‐symmetric cells incorporating NF‐CDs achieve stable cycling for 1600 h at 1 mA cm −2 , while the zinc‐copper cells maintain a 99.67% average coulombic efficiency over 900 cycles. The Zn||NVO (NaV 3 O 8 ·1.5H 2 O) full cell retains a specific capacity of 140 mAh g −1 after 1000 cycles at 5 A g −1 . The results demonstrate the NF‐CDs’ potential as additives for enhancing the stability of ZIBs.