Low-Cost Electrolyte Additive Enables an Ultra-stable and Dendrite-Free Zn Anode

Abstract

With their cost-effectiveness and superior safety features, zincion batteries (ZIBs) have emerged as highly promising energy storage systems. However, severe Zn dendrites and harmful side reactions exist on the Zn surface during cycling, resulting in poor coulombic efficiency (CE) and cycling stability. Herein, the above problems have been solved by adding sodium gluconate (Ga) additive in a 2 M ZnSO 4 (ZSO) electrolyte (ZSO− 0.05Ga). On the one hand, the Ga additive is adsorbed on the surface of the Zn metal anode to form a protective layer, which effectively reduces the corrosion reaction and induces uniform deposition. On the other hand, the strong adsorption capacity between Ga and Zn 2+ in the electrolyte can change the solvation structure of Zn 2+ , thereby effectively inhibiting the generation of side reactions. Thus, a Zn||Zn symmetric battery with a ZSO−0.05Ga electrolyte can be cycled stably for more than 2700 h at a current density of 1 mA cm −2 ; the Zn||Cu half-battery has an ultrahigh stability of 500 cycles; and the average charge−discharge efficiency reaches 99.2%. In addition, the Ga additive greatly improves the cycle stability of the Zn||AC battery (89.3% after 1000 cycles at 1 A g −1 ). This electrolyte additive with co-regulation functions of the solvation shell and interface adsorption effect provides an idea for improving the stability of the Zn anode for further application of ZIBs.

In Situ Construction of a Hydrophobic Honeycomb-like Structured ZnMoO4 Coating Applied for Enhancing Zinc Anode Performance

“…To address the above issues, some strategies such as modification of zinc anodes, , membrane modification design, , and electrolyte composition regulation , have been proposed to improve the electrochemical performance of zinc electrodes. Above all, the surface modification of zinc anodes has been widely of concern at present.…”

Electrolyte Additive Strategies for Safe and High-Performance Aqueous Zinc-Ion Batteries: A Mini-Review

“…Besides, the stable plating/stripping of Zn 2+ ions at the solid (electrode)/liquid (electrolyte) interface is crucial for the long-term cycling of ZIBs. Recently, the strategy of “water in salt” (WIS) electrolytes has been proven to disrupt the hydrogen bond network in conventional aqueous electrolytes, thereby reducing active-H 2 O molecules and altering the original solvation sheath. − Benefiting from the high concentration (≥5 M, M = mol kg H2O –1 ) of Zn salts in the electrolyte system, the distance between Zn 2+ ions and anions is greatly shortened, thereby accelerating the transfer of Zn 2+ ions in aqueous electrolytes. − Of note, the deep-eutectic electrolyte (DEE) almost shields H 2 O molecules, and the ultrahigh concentration (75 M) of Zn salts inhibits the solvation effect, achieving reversible Zn 2+ plating/stripping with high Coulombic efficiency (≥99%). − However, the cost of WIS and DEE systems contradicts the expected environmental friendliness and economic benefits of ZIBs, posing challenges for the rapid commercialization of ZIBs. Besides, the slow ion transmission and viscosity aroused by high concentration electrolytes prevent the performance increase of ZIBs at high current density.…”

Disassociating Lithium Salts in Deep Eutectic Solvents and Inhibiting Aluminum Corrosion for Low-Temperature Lithium–Metal Batteries

“…Metallic lithium (Li) is rightly cited as the anode in rechargeable batteries owing to its high theoretical specific capacity (3860 mAh g –1 ) and the most negative electrode potential (−3.04 V vs SHE). − Unfortunately, its electrochemical performance is severely limited under low-temperature conditions. − Electrolytes, acting as the “blood” of lithium-ion (Li-ion) batteries, are sensitive to temperature . Commercial electrolytes contain ethylene carbonate (EC) components to solvate Li and benefit the formation of solvent-separated ion pair (SSIP) for rapid ion migration at room temperature.…”