Aqueous zinc ion battery electrolyte and application thereof

Abstract

The invention discloses an aqueous zinc ion battery electrolyte and application thereof. The aqueous zinc ion battery electrolyte disclosed by the invention contains solvent water, high-concentrationelectrolyte salt and zinc salt;the zinc salt is a water-soluble salt; the high-concentration electrolyte salt is potassium bis(fluorosulfonyl) imide and / or potassium trifluoromethanesulfonate, and themass molar concentration is not less than 10mol / kg. According to the electrolyte, due to the fact that high-concentration potassium bis(fluorosulfonyl) imide and / or potassium trifluoromethanesulfonate are / is added, a large number of water molecules in the electrolyte can be consumed due to the strong solvation effect, the hydration effect of zinc ions is reduced, and zinc dendrites formed by thezinc ions in dissolution and deposition are inhibited; in addition, the strong solvation effect of the high-concentration electrolyte salt and solvent water molecules can reduce the electrochemical activity of the water molecules, improve the electrochemical window of the electrolyte, reduce the hydrogen evolution reaction, reduce the dissolution effect of zinc, inhibit the decomposition of the water molecules on the surface of the electrode, reduce the corrosion dissolution of the zinc negative electrode and prolong the cycle life of the aqueous zinc ion battery.

Description

technical field [0001] The present application relates to the field of water-based zinc-ion batteries, in particular to an electrolyte solution for water-based zinc-ion batteries and applications thereof. Background technique [0002] Zn-ion batteries based on water-based electrolytes are a low-cost, high-safety, cost-effective new energy storage system, and are expected to replace existing energy storage technologies. At present, the electrolytes of aqueous zinc-ion batteries mainly include zinc sulfate, zinc trifluoromethanesulfonate, zinc perchlorate, zinc chloride, zinc acetate, and zinc nitrate. where ZnSO 4 The main disadvantage is that the positive electrode will produce the discharge by-product Zn 4 (OH) 6 SO 4 ·nH 2 O, and the negative electrode will have more obvious zinc dendrite problems. Zn(CF 3 SO 3 ) 2 The main disadvantage of is that it is expensive and the cost is high; moreover, its solubility is low, resulting in a low voltage window of the electr...

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Problems solved by technology

where ZnSO 4 The main disadvantage is that the positive electrode will produce the discharge by-product Zn 4 (OH) 6 SO 4 ·nH 2 O, and the negative electrode will have obvious zinc dendrite problem

Zn(CF 3 SO 3 ) 2 The main disadvantage is that it is expensive and costly; moreover, its solubility is low, resulting in a low electrolyte voltage window

Zn(ClO 4 ) 2 The main disadvantage is that it has a high overpotential

ZnCl 2 and Zn(CH 3 COO) 2 The main disadvantage is its poor anion stability, which leads to poor electrochemical performance of the battery and low Coulombic efficiency

Zn(NO 3 ) 2 The main disadvantage of Zn is that its nitrate has strong oxidizing properties, which will lead to the degradation of the performance of the zinc anode, which in turn leads to the low coulombic efficiency of the anode.

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