Effect of Electrolyte Additives on the Performance of Zinc Ion Batteries

Abstract

The zinc dendrite growth and by-products formation of rechargeable zinc metal batteries hinder their rapid development as promising energy storage equipment. Herein, we use a composite additive composed of leveling agent and surfactant to improve the ZnSO4 electrolyte system to obtain a zinc anode with reversible electroplating/stripping for high-performance aqueous zinc ion batteries (ZIBs). Benzylidene acetone leveling agent can be adsorbed on the crystal nucleation sites to promote homogeneous nucleation in the zinc deposition process, thus inhibiting the zinc dendrites growth, zinc corrosion, and by-products formation. Alkylphenol ethoxylate can improve the crystallinity of the zinc anode surface and increase the nucleation sites, thus reducing the potential nucleation barrier in the zinc deposition process. In addition, alkylphenol ethoxylate is the carrier of benzylidene acetone, which can cooperate with benzylidene acetone, and further enhance the leveling effect of benzylidene ketone. As a result, the Zn/Zn symmetric battery with ZSO+additive electrolyte displays a small overpotential and good cycle stability for 1000 hours. With the increase in current density, the voltage hysteresis does not severely fluctuate. The Zn/MnO2 battery with ZSO+additive electrolyte can provide a higher capacity (179.7 mAh g -1 ) and longer cycle life (76.6% capacity retention after 200 cycles), which proves that the additives can improve the performance of ZIBs. The composite additive proposed in this work provides a new way to develop high-performance zinc ion batteries.

Leveling the Zn Anode by Crystallographic Orientation Manipulation

“…Thus, introducing a leveling agent into the ZMB’s electrolyte may be an effective way to restrain the growth of Zn dendrites. Some additives with a leveling effect have been reported; − however, there is still no conclusive mechanism for modulating Zn deposition in terms of crystallographic orientation to prove that adding a leveling agent to a mildly acidic aqueous electrolyte can suppress dendrite growth.…”