Tandem desolvation effect enables highly reversible Zn metal anodes

Abstract

Metallic Zn, with its affordability and safety, has been regarded as an attractive anode for aqueous batteries but has suffered from dendrite growth. Here, a tandem desolvation strategy is proposed to stabilize Zn metal anodes by a 4-pyridinecarboxamide (PCA) additive as an example. Theoretical and experimental characterizations demonstrate that the PCA molecular layer adsorbs on the anode surface, as well as the derived ZnS/N-rich solid electrolyte interphase (SEI), can sequentially promote the desolvation of hydrated Zn2+ during the electrodeposition process. This phenomenon, known as the tandem desolvation effect, effectively suppresses Zn dendrite growth and achieves the highest utilization rate of 96.7 % in the Zn||Zn cells. Specifically, the Zn||Zn cells can operate at 10, 20, and 50 mA cm−2 with a deposition capacity of 17 mAh cm−2 for 1200, 1000, and 850 h, respectively. Additionally, the constructed PANI||Zn pouch cells also achieve excellent cycle performance, confirming the feasibility of the tandem desolvation effect. This work enriches the understanding of Zn electrodeposition and provides a new perspective for the development of highly reversible metal anodes.