Fluorosilane Molecular Layer Modification for Remarkably Enhancing Cycling Stability of Zinc Metal Anodes in Aqueous Supercapacitors

ABSTRACT An in situ modification approach was used to construct a fluorosilane protective layer (CHFOSi@Zn) on the surface of zinc metal. The CHFOSi layer exhibits both hydrophobicity and zincophilicity due to the presence of fluorine. It reduces stacking during zinc deposition. It also suppresses dendrite growth by improving the deposition behavior. The Cu//CHFOSi@Zn electrode shows excellent reversibility. It can be cycled for 5000 cycles at 10 mA cm −2 with a coulombic efficiency of 99.9%. In symmetric batteries, the CHFOSi layer also delivers outstanding electrochemical performance. It runs stably for 400 h at 1 mA cm −2 and 1 mAh cm −2 . The assembled zinc‐ion capacitors maintain a high capacity retention rate after 10,000 cycles at 1 A g −1 , with no degradation. This demonstrates an ultra‐long cycle life. These results confirm that the CHFOSi layer can significantly enhance the electrochemical performance of the capacitors.