PFDT Self-Assembled Monolayers for Stable Zinc Anodes in Aqueous Batteries

Aqueous zinc-ion batteries (AZIBs) have emerged as important candidates for next-generation energy storage systems due to the abundance of zinc resources, high theoretical capacity (820 mAh g^-1), good safety, and low cost. However, zinc dendrite growth and corrosion issues severely hinder their practical application. This study prepared a PFDT@Zn-modified electrode by self-assembly of 1H,1H,2H,2H-perfluorodecanethiol (PFDT) on the zinc anode surface. A series of electrochemical performance tests, characterizations, and density functional theory (DFT) calculation results indicate that PFDT forms an ordered perfluorocarbon chain protective layer on the zinc surface via Zn-S covalent bonds, and its strong hydrophobicity blocks electrolyte contact and inhibits hydrogen evolution and corrosion reactions; the C-F bonds construct δ-F···Zn²⁺ zincophilic sites, enhancing the Zn²⁺ transport rate and transference number and optimizing the interfacial electric field distribution; PFDT^- drives Zn²⁺ to deposit preferentially on the low-energy Zn(002) crystal plane through selective adsorption on high-energy crystal planes, thereby achieving dense deposition. Electrochemical tests show that the PFDT@Zn symmetric cell stably cycled for 1750 h at 0.5/0.5 mAh cm^-2 and for 3600 h at 5/1 mAh cm^-2, while the bare Zn only cycled for 431 h. The Coulombic efficiency of Zn||Cu asymmetric cell reached 99.7% after 2000 cycles. The full cell assembled with MnO₂ as the cathode maintained 83.6% capacity retention after 900 cycles at 1 A g^-1, with a 48 h static self-discharge rate of 0.15%. These research findings can provide a basis for designing reversible zinc anodes with high cycling stability.