Stabilization of flake Zn powder anodes via designing functional additives in electrolytes for aqueous Zn ion batteries

Zn powder anodes have attracted much attention in aqueous Zn ion battery applications due to advantages such as low cost and processability. However, the high-activity Zn powder anode faces problems such as side reactions, hydrogen evolution, and dendrites, which limit the cycling stability of the cell. In this work, the high activity of Zn powder is weakened by introducing low-cost erythritol as a functional additive in the ZnSO 4 electrolyte to improve the cycle life of the cell. Both theoretical calculations and empirical evidence demonstrate that the incorporation of erythritol alters the coordination sphere of Zn 2+ and modifies the local molecular architecture of the electrolyte. This modification serves to diminish the reactivity of water molecules, thereby efficaciously suppressing dendrite formation and deleterious ancillary reactions on the zinc powder anode surfaces. Concurrently, erythritol functions as an interfacial cationic captor, enhancing reaction dynamics and facilitating the development of a favorable protective layer throughout the zinc plating/stripping process. Consequently, the symmetric cell paired with an erythritol-containing electrolyte manifests stable cycling performance for an extended duration of 850 h at a current density of 0.288 mA cm −2 and areal capacity of 0.144 mAh cm −2 . Notably, it maintains a cycling life of 400 h even under intensified conditions (2.88 mA cm −2 /1.44 mAh cm −2 ). Furthermore, the constructed Na 2 V 6 O 16 ·3H 2 O full cell illustrated remarkable capacity retention of 155.8 mAh g −1 following 800 cycles at a high rate of 5 A g −1 .