Ultra-stable and highly reversible aqueous zinc metal anodes with high preferred orientation deposition achieved by a polyanionic hydrogel electrolyte

Although aqueous zinc metal batteries (AZMBs) have attractive advantages such as high safety, low cost and eco-friendliness, severe dendrites formation and side reactions of zinc metal anodes cause a serious challenge for commercial applications. Herein, a polyanionic hydrogel electrolyte, poly 2-acrylamido-2-methyl-1-propane sulfonate zinc (PAMPSZn) is firstly designed and synthesized by ion exchange and free-radical polymerization. The PAMPSZn hydrogel electrolyte owns fixed polyanionic chain and restricted Zn2+ transport channels, which can effectively alleviate the side reactions and prevent the formation of Zn dendrites simultaneously. Consequently, the anode-friendly electrolyte not only enables ultra-stable Zn plating/stripping over 4500 h at 1.0 mA cm(-2), but also achieves high preferred orientation deposition during the procedure of repeated plating/stripping. It delivers high reversibility with high initial coulombic efficiency (87.5%) and average coulombic efficiency (99.3%) in Zn/Cu cells at 0.5 mA cm(-2). Zn/V2O5 cells with the developed electrolyte also possess outstanding cycle stability with capacity retention of 80.2% after 400 cycles at 0.5 A g(-1). The PAMPSZn hydrogel electrolyte with unique fixed polyanionic chain and restricted Zn2+ transport channels demonstrates an effective strategy to solve both dendrites formation and side reactions in AZMBs, providing a new opportunity for high performance AZMBs.

Automated summary

The newly designed PAMPSZn hydrogel electrolyte shows effectiveness in alleviating side reactions and preventing Zn dendrites formation in AZMBs, allowing for stable Zn plating/stripping and high preferred orientation deposition during cycles. Compared to traditional electrolytes, it exhibits higher coulombic efficiency and cycle stability in both Zn/Cu and Zn/V2O5 cells.