Interfacial Engineering with a Conjugated Conductive Polymer for a Highly Reversible Zn Anode.

For Zn metal batteries, the Zn anode faces several challenges, including Zn dendrites, hydrogen evolution, and corrosion. These issues are closely related to the Zn deposition process at the electrode/electrolyte interface. Herein, we propose interfacial engineering to protect the Zn anode and induce homogeneous deposition using conjugated cyclized polyacrylonitrile (cPAN) polymer nanofibers. It works as a hydrophobic protective layer that inhibits contact with HO molecules, thus reducing side reactions and enhancing the anticorrosion property. Also, with abundant zincophilic sites on cPAN nanofibers via coordination chemistry, Zn ion transport is promoted and homogeneous dendrite-free Zn deposition is obtained. As a result, the cPAN-coated Zn (cPAN@Zn) anode demonstrates high coulombic efficiency of over 99.9%, high cycling stability of over 2000 h at 1 mA cm, long cycling of over 16 000 cycles at 10 mA cm, and excellent kinetics with a low overpotential below 0.15 V at 50 mA cm. This work provides novel insights into organic interfacial engineering via conjugated polymers in aqueous rechargeable Zn energy storage systems.