Quantifying Asymmetric Zinc Deposition : A Guide Factor for Designing Durable Zinc Anodes

Zinc metal has been recognized as the most promising anode for aqueous energy storage but suffers from severe dendrite growth and poor reversibility. However, the coulombic efficiency (CE) lacks specificity for zinc dendrite growth, particularly in Zn||Zn symmetric cells. Herein, we proposed a novel indicator (f_D) based on the characteristic crystallization peaks to evaluate the growth and distribution of zinc dendrites. As a proof of concept, we adopted triethylenetetramine (TETA) as an electrolyte additive to manipulate the zinc flux for uniform deposition, with a corroborating low f_D value. A highly durable zinc symmetric cell was achieved, lasting over 2500 h at 10 mA cm^-2 and 400 h at a large discharge of depth (10 mA cm^-2, 10 mAh cm^-2). Supported by the low f_D value, the Zn||TETA-ZnSO₄||MnO₂ batteries overcame the sudden short circuit and fast capacity fading. The study provides a feasible method to evaluate zinc dendrites and sheds light on the design of highly reversible zinc anodes. © 2024 Wiley-VCH GmbH.