Interfacial engineering and performance investigation of anodes for aqueous zinc-ion batteries

Abstract

Aqueous zinc-ion batteries (AZIBs) have been increasingly attracting attention as emerging alternatives for energy storage applications on a large scale, benefiting from their inherent safety, low environmental impact, and cost advantages. However, challenges such as dendrite formation and surface deterioration significantly hinder the commercial application of Zn metal anodes, resulting in deteriorated cycling stability and a shortened battery lifespan. To address these issues, an uncomplicated and effective coating strategy was developed to construct a PANI/rGO composite functional layer, which provides abundant zinc-philic sites and a conductive carbon network to regulate Zn2+ deposition and suppress undesired reactions. The PANI/rGO layer not only facilitates uniform ion flux but also enhances interfacial electron transfer, resulting in a substantial reduction in charge-transfer resistance and corrosion current. Electrochemical evaluation demonstrates that the symmetrical cell assembled with PANI/rGO@Zn electrodes exhibits significantly improved performance, delivering stable cycling for approximately 500 hours, whereas bare Zn electrodes fail within less than 100 hours. Furthermore, the advantages of the PANI/rGO-modified Zn anode are further validated in Zn//MnO2 full cells, where the modified system delivers a superior initial discharge capacity (281 mAh g−1) and significantly improved capacity retention (253 mAh g−1 after 200 cycles) compared with the rapid capacity decay observed in the bare Zn-based cell. This work demonstrates an efficient and straightforward strategy to stabilize Zn anodes, in which the composite coating effectively enhances the overall lifespan of the battery, providing design guidance for protective layer engineering and contributing to the practical use of AZIBs in large-scale energy storage technologies.