Controlled Construction and Properties Study of PDMS Coatings for Stabilizing Zinc Metal Anode

Abstract

Polydimethylsilane (PDMS) is a promising coating material. The subject proposes a SiO₂-doped PDMS coating material (defined as SO-PDMS), which is hydrophobic and can help desolvate ions in solution, regulate the electric field distribution on the electrode surface, inhibit the formation of dendrites, and reduce the side reactions such as the evolution of oxygen and hydrogen. SiO₂ is rich in silanol groups, which can coordinate with zinc ions to promote the rapid transport of zinc ions and facilitate the uniform deposition of zinc ions on the anode surface. The SO-PDMS@Zn symmetric battery has a lower overpotential (25 mV) and a cycle life (240 h) much higher than that of the bare Zn-Zn battery during charge-discharge cycles, showing the excellent ability of SO-PDMS to activate rapidly and then remain stable. The SO-PDMS-coated half-cell maintains a good Coulombic efficiency during operation, with an average Coulombic efficiency of 97.21%, and no obvious loss is seen after 130 cycles, showing the high reversibility of the battery reaction. The CA curve shows that SO-PDMS can significantly regulate the ion diffusion on the surface of the Zn anode, which can restrict the Zn ions to nucleate in situ. The full cell using V₂O₅ as the cathode performed well with a considerable capacity increase in the early cycles (240 mAh g^-1 at 2 A g^-1).