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CN-122000432-A - Water-resistant electrolyte for magnesium metal battery and preparation method and application thereof

CN122000432ACN 122000432 ACN122000432 ACN 122000432ACN-122000432-A

Abstract

The invention belongs to the technical field of new energy batteries, and particularly relates to a magnesium metal battery water-resistant electrolyte, a preparation method and application thereof. The magnesium metal battery water-resistant electrolyte is prepared from magnesium salt, metal or non-metal halide, organic ether solvent and borate additive. The water-resistant electrolyte of the magnesium metal battery adopts the borate additive to react with water molecules, so that the content of free water or coordinated water is reduced, meanwhile, components of an electrode/electrolyte interface are improved through preferential decomposition, and more stable SEI/CEI (solid electrolyte interface film/positive electrode electrolyte interface film) is formed, so that the water resistance of the battery is remarkably improved, stable circulation can be still realized after water (especially water with the water content of 0-50000 ppm) is added, and the preparation cost, drying cost and environmental requirements of the magnesium metal battery can be greatly reduced.

Inventors

  • TAN SHUANGSHUANG
  • HUANG XUETING
  • Li Hongai
  • PAN FUSHENG

Assignees

  • 重庆大学
  • 重庆新型储能材料与装备研究院

Dates

Publication Date
20260508
Application Date
20251225

Claims (9)

  1. 1. The water-resistant electrolyte for the magnesium metal battery is characterized by comprising magnesium salt, metal or nonmetal halide, an organic ether solvent and a borate additive.
  2. 2. The magnesium metal battery water-resistant electrolyte according to claim 1, wherein, The magnesium salt is selected from one or more of magnesium chloride, hexafluoroisopropanol magnesium, bis (trifluoromethanesulfonyl) imide magnesium and trifluoromethanesulfonic acid magnesium, and/or The metal or nonmetal halide is selected from one or more of aluminum chloride, boron trichloride, titanium tetrachloride, phosphorus pentachloride, copper chloride, indium chloride, aluminum bromide, indium bromide, aluminum iodide and indium iodide, and/or The organic ether solvent is selected from one or more of 1, 3-dioxolane, 1, 3-dioxane, 1, 4-dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, diethyl cellosolve, 1, 3-dimethoxy propane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether, and/or The borate additive is selected from one or more of trimethyl borate, triethyl borate, triisopropyl borate, tri (2, 2-trifluoroethyl) borate and tri (hexafluoroisopropyl) borate.
  3. 3. The water-resistant electrolyte for a magnesium metal battery according to claim 2, wherein the magnesium salt is magnesium trifluoromethane sulfonate, the metal or nonmetal halide is aluminum chloride, the organic ether solvent is ethylene glycol dimethyl ether, and the borate additive is tris (2, 2-trifluoroethyl) borate.
  4. 4. A magnesium metal battery water resistant electrolyte according to any one of the claim 1 to 3, The molar ratio of magnesium salt to metal or nonmetal halide is 1 (1.0-2.0), and/or The mol ratio of the magnesium salt to the borate additive is 1 (0.5-2.5).
  5. 5. A magnesium metal battery water-resistant electrolyte according to any one of claims 1 to 3, wherein the water content of the magnesium metal battery water-resistant electrolyte is equal to or less than 50000ppm.
  6. 6. The method for preparing the magnesium metal battery water-resistant electrolyte according to any one of claims 1 to 5, which is characterized by comprising the step of mixing magnesium salt, metal or non-metal halide, organic ether solvent and boric acid ester additive to obtain the magnesium metal battery water-resistant electrolyte.
  7. 7. The preparation method according to claim 6, characterized in that the preparation method comprises: (1) Mixing magnesium salt, metal or nonmetal halide and organic ether solvent to obtain magnesium salt solution; (2) And mixing the magnesium salt solution with the borate additive for reaction to obtain the magnesium metal battery water-resistant electrolyte.
  8. 8. Magnesium metal battery characterized by comprising a water-resistant electrolyte of the magnesium metal battery according to any one of claims 1 to 5.
  9. 9. The magnesium metal battery according to claim 8, wherein the magnesium metal battery is a mg||ss battery, a mg||mg symmetrical battery, a mg||mo asymmetrical battery, or a mg||mo 6 S 8 battery.

Description

Water-resistant electrolyte for magnesium metal battery and preparation method and application thereof Technical Field The invention belongs to the technical field of new energy batteries, and particularly relates to a magnesium metal battery water-resistant electrolyte, a preparation method and application thereof. Background The rechargeable magnesium battery (Rechargeable Magnesium Batteries, RMBs) is used as a core candidate direction of the next-generation energy storage technology, has the remarkable advantages of rich magnesium resource reserve, high theoretical volume specific capacity (3833 mAh cm -3), uniform magnesium deposition behavior and the like, can ensure the safety of the operation of the cathode, and is attractive in the field of large-scale energy storage in combination with sustainable resource sources and good economic feasibility. The electrolyte is a key component of RMBs, not only bears the ion transmission function, but also determines the diffusion kinetics of Mg 2+ at the electrode interface, and directly influences the cycle stability and energy efficiency of the battery. However, the commercialization process of RMBs is limited by the extreme sensitivity of the conventional electrolyte to moisture, namely, even if trace moisture remains, irreversible side reactions are induced on the surface of the magnesium negative electrode to form an electrically insulating MgO/Mg (OH) 2 layer, so that the coulombic efficiency and the cycle stability of magnesium deposition/dissolution are seriously reduced, and meanwhile, the high sensitivity of the electrolyte and the magnesium negative electrode to trace moisture remarkably increases the drying cost in the production process of the battery. From the molecular mechanism, water is easy to competitively coordinate with solvent molecules and anions to enter a first solvation shell layer of Mg 2+ due to high dielectric constant and donor number, enrichment and reaction occur on the surface of a negative electrode, the reversibility of deposition/dissolution is weakened, and in addition, the hydrolysis reaction of the anion-water coordination compound consumes active anions and releases free protons (H +), so that electrolyte degradation and parasitic side reaction acceleration are caused. In order to solve the problems, the prior researches try to improve the water resistance by introducing additives, for example, alCl 3 additives can remove water through coordination water capture in a Mg (TFSI) 2 system, but consume active ion species in electrolyte, and partial additives (such as dibutyl magnesium, isobutyl amine, 2-methoxyethylamine and the like) can improve the reversibility of a magnesium anode and remove water impurities, but the water resistance effect of the additives is limited, only 5300ppm of impurity water can be tolerated, and the improvement on coulombic efficiency is limited. Therefore, developing a highly efficient water-resistant electrolyte is critical to achieving a reversible, water-resistant magnesium battery prototype and significantly reducing manufacturing costs. Disclosure of Invention Based on the above, the invention aims to provide a magnesium metal battery water-resistant electrolyte, and a preparation method and application thereof. In order to achieve the above purpose, the present invention may adopt the following technical scheme: The invention provides a magnesium metal battery water-resistant electrolyte, which is prepared from magnesium salt, metal or nonmetal halide, an organic ether solvent and a borate additive. Preferably, in the magnesium metal battery water-resistant electrolyte, The magnesium salt is selected from one or more of magnesium chloride, hexafluoroisopropanol magnesium, bis (trifluoromethanesulfonyl) imide magnesium and trifluoromethanesulfonic acid magnesium, and/or The metal or nonmetal halide is selected from one or more of aluminum chloride, boron trichloride, titanium tetrachloride, phosphorus pentachloride, copper chloride, indium chloride, aluminum bromide, indium bromide, aluminum iodide and indium iodide, and/or The organic ether solvent is selected from one or more of 1, 3-dioxolane, 1, 3-dioxane, 1, 4-dioxane, tetrahydrofuran, ethylene glycol dimethyl ether, diethyl cellosolve, 1, 3-dimethoxy propane, diethylene glycol dimethyl ether, triethylene glycol dimethyl ether and tetraethylene glycol dimethyl ether, and/or The borate additive is selected from one or more of trimethyl borate, triethyl borate, triisopropyl borate, tri (2, 2-trifluoroethyl) borate and tri (hexafluoroisopropyl) borate. More preferably, in the magnesium metal battery water-resistant electrolyte, the magnesium salt is magnesium trifluoromethane sulfonate, the metal or nonmetal halide is aluminum chloride, the organic ether solvent is ethylene glycol dimethyl ether, and the borate additive is tri (2, 2 trifluoroethyl) borate. Preferably, in the preparation method, the molar ratio of the magnesium salt to the