CN-121983684-A - Electrolyte additive and application thereof in water-based zinc-manganese bipolar battery electrolyte

Abstract

The invention provides an electrolyte additive and application thereof in a water-based zinc-manganese bipolar battery electrolyte, relates to the technical field of batteries, and relates to N-octyl pyrrolidone, which belongs to an amphoteric organic substance, wherein the electrolyte additive is a liquid organic substance at room temperature, the molecular structure of the electrolyte additive contains a N-octyl alkyl hydrophobic chain and an amide hydrophilic five-membered ring, and a hydrophilic amide group is helpful to dissolve in an aqueous solution to form an electrolyte with uniform components, has no negative influence on the electrolytic liquid phase structure and only acts on an electrode/electrolyte interface. The hydrophilic group of the interface preferentially adsorbs active sites deposited by zinc and manganese, and the hydrophobic alkyl chain at the tail part discharges active water, so that interface side reactions caused by the interface active water are effectively relieved. In addition, the steric effect can induce uniform deposition of zinc and manganese, and improve the coulomb efficiency and the cycle life of the water system zinc-manganese bipolar battery. The invention improves the performance of the zinc-manganese bipolar battery by adding the electrolyte additive with low cost, and has good application prospect.

Inventors

• AN QINYOU
• Zhang Bomian
• ZHANG LEI
• MAI LIQIANG
• HUANG MENG

Assignees

• 武汉理工大学三亚科教创新园

Dates

Publication Date

20260505

Application Date

20260409

Claims (7)

1. 1. An electrolyte additive, characterized in that the additive is N-octyl pyrrolidone.
2. 2. The use of an electrolyte additive according to claim 1 in aqueous zinc-manganese bipolar battery electrolytes.
3. 3. The use according to claim 2, wherein the electrolyte additive is present in the aqueous zinc-manganese bipolar battery electrolyte in an amount of 0.02% to 0.1% v/v.
4. 4. The use according to claim 3, wherein the aqueous zinc-manganese bipolar battery electrolyte comprises a solute, a solvent and the electrolyte additive.
5. 5. The use according to claim 4, wherein the solute in the aqueous zinc-manganese bipolar battery electrolyte is ZnSO 4 and MnSO 4 ,ZnSO 4 and MnSO 4 with a total concentration of 2mol/L and the concentration ratio of ZnSO 4 and MnSO 4 is 1:1.
6. 6. The use according to claim 4, wherein the solvent is deionized water.
7. 7. The application of the water-based zinc-manganese bipolar battery electrolyte according to claim 4, wherein the preparation method of the water-based zinc-manganese bipolar battery electrolyte comprises the steps of adding a solute into a solvent to prepare a mixed solution, adding an electrolyte additive, vibrating and stirring, and uniformly mixing by ultrasonic to obtain the water-based zinc-manganese bipolar battery electrolyte.

Description

Electrolyte additive and application thereof in water-based zinc-manganese bipolar battery electrolyte Technical Field The invention relates to the technical field of batteries, in particular to an electrolyte additive and application thereof in a water system zinc-manganese bipolar battery electrolyte. Background The water-based zinc-manganese battery has high intrinsic safety and low manufacturing cost, and has great application prospect in the field of large-scale energy storage. In recent years, in order to further increase energy density and simplify the manufacturing process, a "double electrode-less" (no positive and negative electrode active material coating) zinc-manganese battery architecture has been proposed. Under the structure, the anode and the cathode are only formed by bare current collectors when the battery is initially assembled, and the charging and discharging process completely depends on in-situ deposition and stripping of Zn 2+ and Mn 2+ in the electrolyte on the surface of the current collectors. Despite the outstanding theoretical advantages of the bipolar architecture, there are serious challenges of low coulombic efficiency and short cycle life in practical cycles. Because the anode and the cathode are not provided with preset active materials, the electrolyte is not only an ion transmission medium, but also the only source of active substances. Any irreversible loss during deposition/stripping directly results in rapid depletion of the effective ions in the electrolyte. In particular, the degradation of coulombic efficiency and lifetime of a double electrodeless zinc-manganese battery is mainly due to 1. Dendrites and side reactions on the negative side, the bare current collector is extremely prone to induce uneven zinc deposition, leading to uncontrolled growth of zinc dendrites. Meanwhile, serious hydrogen evolution side reaction can occur on the surface of the negative electrode of the water-based electrolyte, so that active zinc can be irreversibly consumed by hydrogen evolution, and local microenvironment can be deteriorated to generate dead zinc. 2. The deposition/stripping of the positive electrode side is irreversible, namely manganese dioxide (MnO 2) deposited during charging has serious problems of dynamics barrier and structural collapse during the discharge stripping process, and a large amount of manganese-based substances which are not successfully converted into Mn 2+ solvent and returned to electrolyte can be changed into dead manganese or pulverized and shed from a current collector. The dead zinc of the negative electrode and the dead manganese of the positive electrode act together, so that the coulomb efficiency of the bipolar battery is rapidly reduced and the capacity is rapidly exhausted after a few cycles. Most of the existing electrolyte additives only aim at a single electrode, for example, only inhibit negative zinc dendrite, and cannot simultaneously give consideration to the high reversibility of metal ion deposition/stripping on double-sided bare current collectors. Therefore, development of a novel dual-function or multifunctional electrolyte additive is needed to comprehensively improve redox reversibility of zinc and manganese ions, fundamentally improve coulombic efficiency of a water-system zinc-manganese bipolar zinc-manganese battery and remarkably prolong cycle life of the water-system zinc-manganese bipolar zinc-manganese battery. Disclosure of Invention In view of the above, the invention provides an electrolyte additive and application thereof in the aqueous zinc-manganese bipolar battery electrolyte. The technical scheme of the invention is realized as follows: an electrolyte additive, wherein the additive is N-octyl pyrrolidone. N-octyl pyrrolidone, N-octylpyrrolidone, C 12H23 NO, has the structural formula: , n-octyl pyrrolidone is an organic substance that is liquid at room temperature, and contains a hydrophobic chain of N-octyl alkyl and an amide hydrophilic five-membered ring in the molecular structure. An application of electrolyte additive in water system zinc-manganese double electrodeless battery electrolyte. Further, the content of the electrolyte additive in the aqueous zinc-manganese bipolar battery electrolyte is 0.02% -0.1% v/v. Further, the aqueous zinc-manganese bipolar battery electrolyte comprises a solute, a solvent and the electrolyte additive. Furthermore, solutes in the aqueous zinc-manganese bipolar battery electrolyte are ZnSO 4, mnSO 4,ZnSO4 and MnSO 4, the total concentration is 2mol/L, and the concentration ratio of ZnSO 4 to MnSO 4 is 1:1. Further, the solvent is deionized water. The preparation method of the water-based zinc-manganese bipolar battery electrolyte comprises the steps of adding a solute into a solvent to prepare a mixed solution, adding an electrolyte additive, vibrating and stirring, and uniformly mixing by ultrasonic to obtain the water-based zinc-manganese bipolar battery electrolyte. Comp