A biomimetic pyrimidine derivative for stabilizing a zinc anode characterized by zinc ion deposition kinetics study and in situ optical imaging

Abstract

Aqueous zinc-ion batteries (ZIBs) are among the most promising rechargeable batteries, but the stability of the zinc anode is severely threatened by corrosion, dendrite formation and growth as well as hydrogen evolution on the Zn anode. Inspired by biomimetic hydrogen bonding in nucleic acids, this study proposed the use of an ecofriendly and low-cost derivative of pyrimidine (one of the central components of nucleic acids), pyrimidine-2-carboxylic acid (PCA), as an electrolyte additive in a ZnSO₄ electrolyte for stabilizing zinc anodes. Results indicate that PCA with zincophilicity and hydrogen bonding could be adsorbed on the zinc anode surface in the ZnSO₄ electrolyte, thus effectively suppressing corrosion and hydrogen evolution reactions (HERs) and the production and growth of zinc dendrites on the zinc electrode surface. Thus, the effectively improved stability of the Zn anode was achieved. The effects of zinc ion deposition kinetics and in situ inhibition of zinc dendrite formation on zinc electrodes by trace PCA are presented. Hence, symmetric Zn‖Zn batteries, including a PCA/ZnSO₄ electrolyte, exhibited excellent cycling performance for 3500 h under 1 mA cm⁻² and 1 mA h cm⁻² and over 2000 h under 5 mA cm⁻² and 1 mA h cm⁻² at 298 K. The coulombic efficiency of Zn‖Cu half-cells containing the PCA/ZnSO₄ electrolyte remained 99.7% after 700 cycles at 5 mA cm⁻² and 5 mA h cm⁻². Under a current density of 1 A g⁻¹, the capacity retention rate of Zn‖Mn full cells with the PCA/ZnSO₄ electrolyte increased by 32% after 1000 cycles compared with that of the blank ZnSO₄ electrolyte. Hence, this study provides insights into strengthening aqueous zinc-ion batteries using a low-cost and ecofriendly dilute pyrimidine derivative in aqueous electrolytes.