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CN-122025810-A - Functional additive for lithium/sodium metal battery electrolyte, and preparation method and application thereof

CN122025810ACN 122025810 ACN122025810 ACN 122025810ACN-122025810-A

Abstract

The invention discloses a functional additive for lithium/sodium metal battery electrolyte, and a preparation method and application thereof, and relates to the technical field of lithium/sodium battery electrolyte preparation. The functional additive is a strippable laminar material with permanent positive charges and is stably suspended in the electrolyte of the lithium/sodium metal battery. The functional additive has anion adsorption selectivity and migration targeting. By utilizing an interface electrostatic adsorption-electric field driven migration mechanism of suspended positively charged particles, a layer of solid electrolyte interface film which is compact and rich in sodium fluoride is constructed on the surface of a sodium metal negative electrode in situ, and dendrite growth is obviously inhibited, so that the cycle life and coulomb efficiency of the battery are improved. The invention solves the problem of dendrite growth of the existing lithium/sodium metal battery.

Inventors

  • LIU SHUO
  • YANG WENSHENG
  • CAO YU
  • SUN JIE
  • Lu Longyue

Assignees

  • 衢州资源化工创新研究院
  • 北京化工大学

Dates

Publication Date
20260512
Application Date
20260129

Claims (10)

  1. 1. A functional additive for lithium/sodium metal battery electrolyte, characterized in that the functional additive is a strippable laminar material with a permanent positive charge and is stably suspended in the lithium/sodium metal battery electrolyte.
  2. 2. The functional additive for lithium/sodium metal battery electrolyte according to claim 1, wherein the functional additive is a nano-sheet with a single-layer structure or a multi-layer structure, the functional additive is nano-particles with a single-layer structure or a multi-layer structure, the size of the functional additive is 0.3 nm-5 μm, and the Zeta potential of the functional additive is +5- +50 mV.
  3. 3. The functional additive for lithium/sodium metal battery electrolyte according to claim 1, wherein the concentration of the functional additive in the electrolyte is 0.25-2 mg/mL.
  4. 4. The lithium/sodium metal battery electrolyte functional additive according to claim 1, wherein the functional additive is hydrotalcite and/or hydrotalcite-like.
  5. 5. The functional additive for lithium/sodium metal battery electrolyte according to claim 4, wherein the hydrotalcite and hydrotalcite-like layered plates are each composed of a metal hydroxide and have a permanent positive charge.
  6. 6. The functional additive for lithium/sodium metal battery electrolyte according to claim 5, wherein the hydrotalcite and hydrotalcite-like compound are prepared by the following methods: (1) Mixing metal salts with different valence states with deionized water to prepare mixed salt solution; (2) Mixing the mixed salt solution prepared in the step (1) with an aqueous solution containing sodium carbonate and sodium hydroxide, stirring and aging, and then centrifuging, washing and drying to prepare a precursor; (3) Adding an intercalation stripping agent into the precursor prepared in the step (2), ball milling, adding a polar dispersion medium, performing ultrasonic stripping, and drying to obtain the product.
  7. 7. The functional additive for lithium/sodium metal battery electrolyte according to claim 6, wherein the metal salt ions of different valence states are at least 2 of Li + 、Na + 、K + 、Mg 2+ 、Zn 2+ 、Ni 2+ 、Co 2+ 、Ca 2+ 、Cu 2+ 、Al 3+ 、Fe 2+ 、Cr 2+ and Ga 2+ .
  8. 8. Use of the lithium/sodium metal battery electrolyte functional additive according to any one of claims 1-7 in the preparation of a lithium/sodium metal battery electrolyte.
  9. 9. A lithium/sodium metal battery electrolyte, characterized by comprising an electrolyte salt, an organic solvent and the lithium/sodium metal battery electrolyte functional additive according to any one of claims 1 to 7.
  10. 10. A lithium/sodium metal battery comprising a positive electrode, a negative electrode, a separator and the lithium/sodium metal battery electrolyte according to claim 9.

Description

Functional additive for lithium/sodium metal battery electrolyte, and preparation method and application thereof Technical Field The invention relates to the technical field of lithium/sodium battery electrolyte preparation, in particular to a functional additive for lithium/sodium metal battery electrolyte, and a preparation method and application thereof. Background Lithium metal and sodium metal batteries are considered to be powerful competitors for the next generation of high energy density energy storage systems due to their extremely high theoretical specific capacities of the negative electrodes (3830 mAh g -1 and 1166 mAh g -1, respectively). However, the commercialization process of lithium/sodium metal batteries still faces challenges, in which dendrite growth of the metal negative electrode caused by uneven ion flow and deposition kinetics during charge and discharge is one of the important problems, and dendrite growth may puncture the separator, resulting in internal short circuit of the battery, shortened cycle life, and even potential safety hazard. The core of the solution to the dendrite growth problem is to optimize the metal negative electrode/electrolyte interface, and the conventional method comprises (1) using a high concentration electrolyte to form an anion-dominated solvating sheath layer to promote the formation of an inorganic-rich solid electrolyte interface film (SEI), (2) introducing a functional additive (such as vinylene carbonate or fluoroethylene carbonate, etc.), and forming a more stable interface layer by preferential reduction thereof, (3) constructing an artificial SEI layer or designing a three-dimensional structure on a current collector to physically restrict the deposition of sodium. However, the high-concentration electrolyte has high cost, high viscosity and poor wettability, particularly for the common hexafluorophosphate electrolyte, fluoride generated by decomposing the anion PF 6- is an excellent SEI component, but the reduction potential is relatively late, the decomposition process is random and uncontrollable, the SEI film formed by decomposing the traditional organic additive has limited mechanical strength, the regulation and control on the anion behavior are passive and random, and the artificial SEI layer or the three-dimensional host is complex in process and difficult to apply in large scale. The positively charged strippable layered material is a material with a specific layered structure and positive charges on the surface, has excellent anion adsorption capacity and interface regulation potential, can adsorb and enrich anions by virtue of unique charge properties, and can form a synergistic migration effect with solvated metal ions. At present, a positively charged layered material is not introduced into a battery electrolyte system as a movable suspended component, and the charged attribute and the mobility of the positively charged layered material actively regulate and control an interface electrochemical process, so that relevant reports of an SEI film are optimized. Therefore, developing a universal interface regulation strategy based on positively charged lamellar suspension additive has great significance for improving the performance and safety of lithium metal and sodium metal batteries. Disclosure of Invention In order to solve the technical problems, the invention aims to provide a functional additive for an electrolyte of a lithium/sodium metal battery, and a preparation method and application thereof, so as to solve the problem of dendrite growth of the existing lithium/sodium metal battery. The technical scheme for solving the technical problems is as follows, the functional additive of the lithium/sodium metal battery electrolyte is provided, the functional additive is a strippable laminar material with permanent positive charges, and the functional additive is stably suspended in the lithium/sodium metal battery electrolyte. Based on the technical scheme, the invention can also be improved as follows: Further, the functional additive is a nano-sheet with a single-layer structure or a multi-layer structure, the functional additive is a nano-particle with a single-layer structure or a multi-layer structure, the size of the functional additive is 0.3 nm-5 mu m, and the Zeta potential of the functional additive is +5- +50 mV. Further, the functional additive has a size of 30-100 nm. Further, the functional additive has a size of 30-50 nm. Further, the functional additive has a size of 50-100 nm. Further, the concentration of the functional additive in the electrolyte is 0.25-2 mg/mL. Further, the concentration of the functional additive in the electrolyte was 1 mg/mL. The further technical scheme has the beneficial effects that the concentration is enough to generate a remarkable effect on the interface, and meanwhile, excessive solid particles are prevented from increasing the resistance of the electrolyte or causing other side react