CN-122025855-A - Ionic liquid-based high-pressure quick-charging electrolyte and preparation method thereof

Abstract

The invention discloses an ionic liquid-based high-pressure quick-charging electrolyte and a preparation method thereof, wherein the preparation method of the electrolyte comprises the steps of mixing 1-ethyl-3-methylimidazole trifluoro methanesulfonate, zinc trifluoro methanesulfonate and a trace amount of deionized water to obtain a mixed solution A; and adding tetramethyl guanidine hydrochloride into the electrolyte, stirring the electrolyte at 60-80 ℃ for reaction, cooling the electrolyte, and continuing stirring and aging the electrolyte. The deionized water is added in an amount of 60-100 mu L per milliliter of ionic liquid, and the concentration of the tetramethylguanidine hydrochloride in the mixed solution is 30-80 mM. According to the invention, through the synergistic effect of the ionic liquid matrix and the guanidine salt additive, the zinc ion solvation structure is regulated and controlled, so that the ionic conductivity is remarkably improved and the interface impedance and zinc deposition overpotential are reduced while a wide electrochemical stability window is realized. The zinc ion battery assembled by the electrolyte has the advantages of high energy density, excellent rapid charge and discharge capacity and cycle stability, simple preparation process and suitability for large-scale application.

Inventors

• TANG SHAOCHUN
• YE CHENGWEI

Assignees

• 南京大学
• 海安南京大学高新技术研究院

Dates

Publication Date

20260512

Application Date

20260228

Claims (5)

1. 1. The preparation method of the ionic liquid-based high-pressure quick-charging electrolyte is characterized by comprising the following steps of: Mixing an ionic liquid, a zinc salt and deionized water, and uniformly stirring at room temperature to obtain a mixed solution A, wherein the ionic liquid is 1-ethyl-3-methylimidazole trifluoro methanesulfonate, and the zinc salt is zinc trifluoromethanesulfonate; Step two, adding a certain amount of tetramethylguanidine hydrochloride into the mixed solution A, and stirring for 0.5-2 hours at 60-80 ℃ to obtain a mixed solution B; step three, cooling the mixed solution B to room temperature, and continuously stirring for 8-16 hours to obtain the ionic liquid-based high-voltage quick-charge electrolyte; and the adding amount of the deionized water is 60-100 mu L based on each milliliter of the ionic liquid.
2. 2. The preparation method of claim 1, wherein the concentration of the tetramethylguanidine hydrochloride added to the mixed solution is 30-80 mM.
3. 3. The method of claim 2, wherein the tetramethylguanidine hydrochloride is added in an amount of 50mM.
4. 4. An ionic liquid-based high-voltage fast-charge electrolyte prepared by the preparation method according to any one of claims 1 to 3.
5. 5. A zinc-ion battery comprising the ionic liquid-based high-voltage fast-charge electrolyte of claim 4.

Description

Ionic liquid-based high-pressure quick-charging electrolyte and preparation method thereof Technical Field The invention relates to the technical field of electrolyte preparation, in particular to an ionic liquid-based high-pressure quick-charging electrolyte and a preparation method thereof. Background The water-based zinc ion battery with the characteristics of high safety, low cost, environmental friendliness and the like is taken as an emerging electrochemical energy storage technology, and is widely paid attention in recent years. However, its practical application is limited by energy density, one of the core bottlenecks is the narrow electrochemical stability window of aqueous electrolytes (typically < 2.0V). The free water molecules in the electrolyte are easy to cause side reactions such as hydrogen evolution, oxygen evolution and the like at the electrode interface, and the working voltage and the energy density are severely limited. In order to widen the electrochemical stability window, researchers have proposed new electrolyte constitutions such as a water-in-salt electrolyte and an organic molecule crowded electrolyte. The salt-coated electrolyte produces a high-concentration salt solution by greatly increasing the content of electrolyte salt in an aqueous solvent. The electrolyte effectively reduces the free water content and reduces the activity of water molecules, thereby increasing the electrochemical stability window of the electrolyte. The cost of the electrolyte is significantly increased due to the addition of the high concentration salt. The organic molecule crowded electrolyte uses cheap organic molecules as crowding agents to replace part of electrolyte salt, and the purpose of reducing the activity of water molecules is achieved by stabilizing the dissociation of water through the hydrogen bonding action between the crowding agents and the water molecules. However, due to the characteristic of high concentration, the electrolyte has the characteristics of higher system viscosity, lower ionic conductivity, higher charge transfer resistance at the electrode/electrolyte interface and slower charge transfer kinetics of the overall electrolyte. Eventually resulting in a relatively low battery capacity, long-term cycling stability, and charge storage efficiency. In recent years, ionic liquids are explored as electrolyte matrixes of zinc batteries due to extremely low volatility, high thermal stability and wide electrochemical window, and are expected to radically break through voltage bottlenecks. However, the pure ionic liquid or the conventional ionic liquid-based electrolyte is generally high in viscosity, and the zinc ion migration and interface desolvation processes are slow, so that the capacity of the battery is rapidly attenuated at high multiplying power, and the high-voltage performance and the fast charge performance are difficult to be combined. Therefore, developing a novel ionic liquid-based electrolyte with a wide voltage window and rapid charge transmission dynamics has become a technical problem to be solved in the application of zinc ion batteries with high energy density and high power density. Disclosure of Invention The embodiment of the application solves the technical problems that the electrochemical window and the ionic conductivity of the traditional ionic liquid-based zinc electrolyte are difficult to obtain and the interfacial charge transfer impedance is large by providing the ionic liquid-based high-voltage quick-charge electrolyte and the preparation method thereof, and the solvation structure and the interfacial transmission process of zinc ions are cooperatively regulated and controlled by introducing a specific guanidine salt additive into a high-stability ionic liquid matrix, so that the ionic conductivity is obviously improved, the interfacial impedance and the zinc deposition overpotential are reduced while the wide electrochemical stability window is maintained, and the high-voltage stable operation and the quick charge and discharge capacity of the zinc ion battery are realized. The embodiment of the application provides a preparation method of an ionic liquid-based high-pressure quick-charge electrolyte, which comprises the following steps: Mixing an ionic liquid, a zinc salt and deionized water, and uniformly stirring at room temperature to obtain a mixed solution A, wherein the ionic liquid is 1-ethyl-3-methylimidazole trifluoro methanesulfonate, and the zinc salt is zinc trifluoromethanesulfonate; Step two, adding a certain amount of tetramethylguanidine hydrochloride into the mixed solution A, and stirring for 0.5-2 hours at 60-80 ℃ to obtain a mixed solution B; step three, cooling the mixed solution B to room temperature, and continuously stirring for 8-16 hours to obtain the ionic liquid-based high-voltage quick-charge electrolyte; and the adding amount of the deionized water is 60-100 mu L based on each milliliter of the ionic liquid. Prefer