In situ construction of zinc-rich polymeric solid–electrolyte interface for high-performance zinc anode

With their excellent reliability and environmental friendliness, zinc-ion batteries (ZIBs) are regarded as potential energy storage technologies. Unfortunately, their poor cycling durability and low Coulombic effectiveness (CE), driven by dendritic growth and surface passivation on the Zn anode, severely restrict their commercialization. Herein, we describe the in situ construction of a Zn-rich polymeric solid–electrolyte interface (SEI) using polyacrylic acid (PAA) as an electrolyte additive. On the one hand, the PAA SEI layer offers evenly distributed nucleation sites and promotes ion transport, hence suppressing dendrite growth. On the other hand, the SEI layer prevents direct contact between the Zn foil and the electrolyte, thus inhibiting side reactions. Additionally, the robust coordination of PAA with Zn²⁺ and the SEI layer's good adherence to the Zn foil provide long-term protection to the Zn anode. As a result, symmetric cells and Zn/V₂O₅ cells all deliver prolonged cycle life and superior electrochemical efficiency.