Thermal‐Cyclized Polyacrylonitrile Artificial Protective Layers Toward Stable Zinc Anodes for Aqueous Zinc‐Based Batteries

Abstract Aqueous Zn‐based batteries (AZBs) have appealed numerous attentions in the energy storage field due to their low cost, environmental friendliness and high safety. However, the Zn metal anode faces severe challenges of short cycle life because of the dendrite growth and side reactions, which hinders the practical application of AZBs. Herein, an artificial coating layer of cyclized polyacrylonitrile (cPAN) is designed on the Zn anode through spin‐coating and thermal treatment. The cPAN layer possesses abundant N‐containing groups and delocalized π‐conjugation structure, which endows the Zn anode with low nucleation barrier and homogeneous electric field. Benefiting from these synergetic advantages, the nucleation overpotential of Zn is remarkably decreased. Furthermore, no obvious byproduct is observed on the cPANZ‐Zn after cycling. As a result, the resultant cPANZ‐Zn anode delivers a long lifespan of 600 h and high reversibility. cPANZ‐Zn||MnO 2 full cells are further assembled and exhibited stable cycling and high rate capability.