Insights into Chemical and Electrochemical Interactions between Zn Anode and Electrolytes in Aqueous Zn−ion Batteries

Abstract

Aqueous Zn-ion batteries (ZIBs) have garnered significant interest in recent years due to their potential applications in large-scale stationary energy storage. Early ZIB research has primarily focused on searching for better cathodes and understanding cathodic Zn2+ storage mechanisms. Only very recently has ZIB research shifted to the Zn anode. Here, we report on insights into the interactions between the Zn anode and aqueous Zn-salt electrolytes gained by a systematic investigation of bulk properties of electrolytes, surface properties of the reacted Zn, electrokinetics of Zn/Zn2+ redox reaction, and cycle stability of Zn/electrolyte/Zn symmetrical cells. We found that Zn metal surface, regardless of electrolyte, are always covered by a layer of Zn-containing layered double hydroxides (Zn-LDHs) upon contact with aqueous Zn-electrolytes. We show that “OH- production” pathway resulted from the dissolved oxygen in Zn-electrolytes is the root cause for the Zn-LDHs formation. The electrokinetic studies reveal that Zn/Zn(ClO4)2 interface has the highest exchange current density, while the symmetrical cell tests show that Zn(OTf)2 is the most stable electrolyte for Zn-metal anode.

Protecting Zn anodes by atomic layer deposition of ZrO2 to extend the lifetime of aqueous Zn-ion batteries

“…The ohmic resistance ( R o ) and charge transfer resistance ( R ct ) were extracted using an equivalent circuit developed in our previous study. 20 A clear reduction in R o from 5.7 Ω cm 2 of bare Zn to 4.1–1.4 Ω cm 2 of ALD-ZrO 2 @Zn are observed in Fig. 4(a) and Fig.…”

“…Details of the methods have been described in our previous work. 20 It is worth mentioning that a relatively stable OCP was first achieved after the assembly of the cell. In this study, ALD-ZrO 2 @Zn, Ag/AgCl, and Pt were used as the working electrode (WE), reference electrode (RE), and counter electrode (CE), respectively, while 2 M ZnSO 4 was the electrolyte.…”

Anti‐Fatigue Hydrogel Electrolyte for All‐Flexible Zn‐Ion Batteries

“…The kinetics and corrosion‐resistance features of the C‐PAMCS are first disclosed by electrochemical measurements. As illustrated in Figure a, 2 M Zn(ClO 4 ) 2 aqueous electrolyte (AE) exhibits an ionic conductivity of 31.6 mS cm −1 , [ 23 ] slightly decreasing to 23.1 and 22.6 mS cm −1 for C‐PAM and C‐PAMCS, respectively. It shows that polymerization has a mild impact on ionic conductivity.…”

Advancements, challenges, and applications of rechargeable zinc‐ion batteries: A comprehensive review

“…Recent studies primarily focus on ZnSO 4 's potential to enhance specific capacity and performance relative to concentration [62,63]. Other species reportedly used for ZIBs include ZnCl 2 [64], Zn(CH 3 COO) 2 [65], Zn(NO 3 ) 2 [66], and ZnBr 2 [67]. Tang et al [64] for example, utilized ZnCl 2 used for V 2 -O 5 -Zn battery and the results of their study revealed that it enabled proton insertion, enhanced the reversibility and prolonged life span.…”