An amphoteric betaine electrolyte additive enabling a stable Zn metal anode for aqueous batteries

Abstract

An amphoteric compound of betaine is demonstrated as an electrolyte additive for aqueous zinc batteries. It forms hydrogen bonds with water and preferentially adsorbs on the Zn surface, which inhibits side reactions and ensures uniform Zn deposition.

Surface Control Behavior toward Crystal Regulation and Anticorrosion Capacity for Zinc Metal Anodes

“…In addition, to investigate the interaction effect of APG with H 2 O molecules, FTIR spectra of ZS, ZS@APG0.15, ZS@APG0.065, and ZS@APG0.5 electrolytes were tested and are collected in Figures S5 and S6. The shift peak locations after the addition of APG additives as compared with the pure ZS electrolyte indicate that the interaction of APG with H 2 O can decrease the activity of H 2 O and reduce H 2 O-induced parasitic reaction on the Zn surface. , …”

“…To investigate quantitatively the effect of APG additives on the corrosion ability of Zn metal anodes, linear scanning voltage (LSV) curves were tested at the scan speed of 0.2 mV s –1 between −1.2 V and −0.5 V and are recorded in Figure b. The higher corrosive potential (−0.987 V) and lower current (0.040 mA) with ZS@APG0.15 electrolytes than pure ZS electrolyte (−1.0 V and 0.152 mA) demonstrate the enhancement of anticorrosion ability after the introduction of APG additives in aqueous electrolyte, resulting from the destruction of the Zn­(H 2 O) 6 2+ shell and the generation of the Zn(002) plane with high H 2 adsorption free energy and strong inner chemical bonds . The corrosive potential and current with ZS@APG0.15 electrolytes are higher and lower than that of ZS@APG0.065 (−0.995 V and 0.057 mA) and ZS@APG0.5 (−0.986 V and 0.063 mA) electrolytes (Figure S12), respectively, indicating that the suitable concentration of the APG additive in aqueous electrolyte can obviously enhance the anticorrosion capacity of Zn metal anodes.…”

An “immobilizing and relocating” strategy for a highly reversible metallic zinc anode

“…Unfortunately, the achieved performance in a previous attempt is still limited. 35 This indicates that the mechanism behind this idea is truly complex, and more profound exploration is urgently needed.…”

Enabling uniform zinc deposition by zwitterion additives in aqueous zinc metal anodes

“…The anionic groups can form a solvation structure with Zn 2+ and lower the reactivity of water molecules. [21][22][23] The cation groups adsorb near the zinc metal surface and regulate the Zn 2+ adsorption. 21,22 Moreover, the anion tail of zwitterions can repel the water molecules and other anions, such as SO 4 2− from the zinc metal surface and reduce ZBS formation.…”

“…[21][22][23] The cation groups adsorb near the zinc metal surface and regulate the Zn 2+ adsorption. 21,22 Moreover, the anion tail of zwitterions can repel the water molecules and other anions, such as SO 4 2− from the zinc metal surface and reduce ZBS formation. 22,23 Herein, due to the unique ability of zwitterions, we use 6aminohexanoic acid (abbreviated as 6-AA) as an electrolyte additive.…”