Interfacial electric field and desolvation regulation via conducting polymer interphase enables stable zinc anode

Abstract

Practical implementation of Zn metal anodes boasting high volumetric capacity is significantly limited by dendritic growth and associated interfacial parasitic reactions. In this paper, the conductive polymer PANI is rationally designed as an interfacial layer to regulate the Zn²⁺ deposition to obtain a stable Zn anode. Finite element simulations and experiments reveal that PANI accelerates the Zn²⁺ transport kinetics via Coulombic gravity during the deposition/stripping process, which results in uniform interfacial charge distribution and Zn deposition. Furthermore, Electrochemical analysis and density-functional theory (DFT) calculations indicate that the amine (-NH-) and imine (-N=) groups on the PANI chains immobilize the H₂O molecules near Zn²⁺, which effectively reduced the migration energy barrier of Zn²⁺ by facilitating desolvation of Zn²⁺. Therefore, the PANI layer enables uniform Zn deposition via synergistic interfacial electric field effects and controlled Zn²⁺ desolvation. The PANI@Zn anode achieves a high average Coulombic efficiency of 99.5 % over 750 cycles. Additionally, the PANI@Zn//MnO₂ full cell delivers stable cycling for 2000 cycles at 1 A g⁻¹. This study offers novel insights into conducting polymer interphases for high-performance Zn-ion batteries.