Synergistic Regulation of Deep-Cycling-Induced Zn Pulverization and Resting Galvanic Corrosion in Practical Lean Zinc...

Scaling up aqueous zinc (Zn)-ion batteries with long cycling stability and calendar life (i.e., long rest periods at open-circuit potential) remains challenging, particularly with the use of a thick Zn foil anode. A more practical and scalable approach involves adopting a lean-Zn configuration with a current collector. Due to the limited Zn availability, lean Zn anodes experience different failure mechanisms, manifested as Zn pulverization in cycle life and galvanic corrosion during calendar life. Unfortunately, these issues have long been overlooked. Herein, we introduce benzotriazole (BTA), a well-known corrosion inhibitor, as an electrolyte additive in aqueous zinc sulfate (ZnSO₄) electrolytes. BTA modifies the electric double layer (EDL) structure on the Zn anode, alleviating the mismatch between Zn^{2 +} mass transport and reduction kinetics. This leads to the formation of dense, flat zinc deposits rather than the Zn pulverized structures, significantly reducing contact loss during stripping. On the other hand, the strong chemisorption of BTA on the Cu substrate effectively blocks electron transfer pathways responsible for galvanic corrosion, reducing capacity fade during calendar aging. When paired with a MnO₂ cathode, the lean-Zn anode enables the full cell to retain 90.3% of its capacity over 600 cycles at a negative: positive (N:P) ratio of 3:1.