Hyperbranched polyamidoamine protective layer with phosphate and carboxyl groups for dendrite-free Zn metal anodes

Zinc metal is regarded as one of the most promising anodes for Zn-based batteries in next-generation energy storage systems. However, the dendrite growth and interfacial corrosion lead to poor reversibility and cycle life of Zn anodes. Herein, we synthesize a 2-phosphate-1,2,4-butane tricarboxylic acid modified hyperbranched polyamidoamine containing rich terminal groups of phosphate and carboxyl (HPC) as modified layer for the Zn anodes. Importantly, the in situ acid-etching promotes the exposure of (002)Zn plane and the generated salt-polymer complexes could be adhered to the Zn anodes tightly. This greatly favors the uniform deposition of Zn and inhibits interfacial corrosion. Consequently, stable HPC@Zn anode plating/stripping for over 1200 h at a high areal capacity of 4 mAh/cm2 and a current density of 4 mA/cm2 is obtained. This study provides a new avenue of hyperbranched polymer in interfacial design for highly reversible and stable Zn metal anodes. An interfacial functional layer of 2-phosphate-1,2,4-butane tricarboxylic acid (PBTCA) modified hyperbranched polyamidoamine has been constructed on Zn metal. The bifunctional groups of phosphate and carboxyl work as binding sites and adhere tightly to the Zn anode via a facile surface chemistry, leading to preferential exposure of (002)Zn plane and uniform Zn plating for dendrite-free Zn metal anodes. [Display omitted]