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CN-122025747-A - Organic bentonite mixed solid-liquid electrolyte and preparation method and application thereof

CN122025747ACN 122025747 ACN122025747 ACN 122025747ACN-122025747-A

Abstract

The invention provides an organic bentonite mixed solid-liquid electrolyte and a preparation method and application thereof, and belongs to the technical field of lithium ion battery electrolytes. The lithium ion battery electrolyte can meet the use requirement of the lithium ion battery by limiting the types of the organic solvents, can ensure that the electrolyte has better structural stability by limiting the mass relation of the organic solvents and the organic bentonite, can change the polarity of a system and influence intermolecular acting force by adding the lithium salt, improves the viscosity of the electrolyte and further improves the structural stability of the electrolyte, can form an ion conduction channel when used as the electrolyte of the lithium ion battery, realizes uniform interface deposition and deintercalation, inhibits the growth of lithium dendrites, reduces interface impedance, and effectively blocks the shuttling of free active substances by the uniform interface so as to improve the cycling stability of the lithium ion battery.

Inventors

  • HAN CHAOYANG
  • Yang Hangqi
  • NIU XIAOTONG

Assignees

  • 中原科技学院

Dates

Publication Date
20260512
Application Date
20260304

Claims (10)

  1. 1. The organic bentonite mixed solid-liquid electrolyte comprises organic bentonite, an organic solvent and lithium salt, wherein a three-dimensional network structure is formed by interaction of a lamellar layer of the organic bentonite and the organic solvent through non-covalent bonds, the lithium salt is dispersed in the three-dimensional network structure, the organic solvent is one or more of carbonate and ether organic solvents, the mass content of the lithium salt in the organic bentonite mixed solid-liquid electrolyte is 3-8%, and the mass content of the organic solvent is 5% -10%.
  2. 2. The organobentonite mixed solid-liquid electrolyte of claim 1 wherein the carbonate-based organic solvent comprises one or more of dimethyl carbonate, ethylene carbonate and diethyl carbonate.
  3. 3. The organobentonite mixed solid-liquid electrolyte according to claim 1, wherein the ether-based organic solvent includes one or both of 1, 3-dioxolane and tetrahydrofuran.
  4. 4. The organobentonite mixed solid-liquid electrolyte of claim 1 wherein the lithium salt comprises one or more of lithium bistrifluoromethanesulfonimide, lithium hexafluorophosphate and lithium perchlorate.
  5. 5. The organic bentonite mixed solid-liquid electrolyte according to claim 1, wherein the organic bentonite is quaternary ammonium salt modified bentonite, and the mass fraction of bentonite in the quaternary ammonium salt modified bentonite is 65-75%.
  6. 6. The organobentonite mixed solid-liquid electrolyte according to claim 5, wherein the quaternary ammonium salt in the quaternary ammonium salt modified bentonite includes one or both of cetyltrimethylammonium bromide and dodecyldimethylbenzyl ammonium chloride.
  7. 7. The method for preparing the organic bentonite mixed solid-liquid electrolyte according to any one of claims 1 to 6, which is characterized by comprising the steps of mixing organic bentonite, an organic solvent and lithium salt and then performing physical gelation to obtain the organic bentonite mixed solid-liquid electrolyte.
  8. 8. The method according to claim 7, wherein the temperature of the physical gelation is 25 to 60 ℃ and the time of the physical gelation is 3 to 9 hours.
  9. 9. A lithium ion battery comprising a positive electrode, a negative electrode and an electrolyte, wherein the electrolyte is the organobentonite mixed solid-liquid electrolyte according to any one of claims 1 to 6 or the organobentonite mixed solid-liquid electrolyte prepared by the preparation method according to any one of claims 7 to 8.
  10. 10. The lithium ion battery of claim 9, wherein the positive electrode comprises a lithium sheet electrode or a sulfur-carbon composite positive electrode, and the negative electrode comprises a lithium sheet electrode or a graphite negative electrode.

Description

Organic bentonite mixed solid-liquid electrolyte and preparation method and application thereof Technical Field The invention belongs to the technical field of lithium ion battery electrolytes, and particularly relates to an organic bentonite mixed solid-liquid electrolyte, a preparation method and application thereof. Background The electrolyte is a core component of the lithium ion battery and plays roles of lithium ion conduction and electrode isolation. At present, a commercial lithium ion battery mainly adopts a liquid electrolyte, but the liquid electrolyte has the problems of easy liquid leakage, poor safety (easy combustion explosion initiation), insufficient compatibility with high-activity electrodes (such as lithium metal and sulfur positive electrodes) and the like. For example, in lithium-sulfur batteries, the liquid electrolyte can cause free active material shuttling effect, resulting in rapid capacity decay, in lithium metal batteries, the liquid electrolyte can easily induce lithium dendrite growth, resulting in short circuit risk, in lithium-on-graphite batteries, the liquid electrolyte forms an SEI film on the surface of the graphite negative electrode that is not sufficiently stable, and can easily crack and reconstruct during cycling, resulting in reduced coulombic efficiency and reduced cycle life. Although the solid electrolyte can solve the problems of liquid leakage and safety, the solid electrolyte has the advantages of complex preparation process, high cost, low ionic conductivity (especially at room temperature), poor contact with an electrode interface and difficult large-scale commercial application. The semi-solid electrolyte combines the advantages of high ionic conductivity of liquid electrolyte and high safety of solid electrolyte, and becomes a research hot spot. However, the existing semi-solid electrolyte relies on polymers and inorganic nano particles to construct a framework, has limited blocking effects on polysulfide and dendrite, and has poor cycle performance of the prepared lithium ion battery. Disclosure of Invention The invention aims to provide an organic bentonite mixed solid-liquid electrolyte, a preparation method and application thereof. The organic bentonite mixed solid-liquid electrolyte provided by the invention can effectively block polysulfide and dendrite, and improves the cycle stability of the battery. In order to achieve the above object, the present invention provides the following technical solutions: The invention provides an organic bentonite mixed solid-liquid electrolyte which comprises organic bentonite, an organic solvent and lithium salt, wherein a three-dimensional network structure is formed by interaction of a lamellar layer of the organic bentonite and the organic solvent through non-covalent bonds, the lithium salt is dispersed in the three-dimensional network structure, the organic solvent is one or more of carbonate and ether organic solvent solvents, the mass content of the lithium salt in the organic bentonite mixed solid-liquid electrolyte is 3-8%, and the mass content of the organic solvent is 5-10%. Preferably, the carbonate-based organic solvent includes one or more of dimethyl carbonate, ethylene carbonate, and diethyl carbonate. Preferably, the ether-type organic solvent includes one or both of 1, 3-dioxolane and tetrahydrofuran. Preferably, the lithium salt comprises one or more of lithium bistrifluoro methanesulfonimide, lithium hexafluorophosphate and lithium perchlorate. Preferably, the organic bentonite is quaternary ammonium salt modified bentonite, and the mass fraction of bentonite in the quaternary ammonium salt modified bentonite is 65-75%. Preferably, the quaternary ammonium salt in the quaternary ammonium salt modified bentonite comprises one or two of cetyltrimethylammonium bromide and dodecyldimethylbenzyl ammonium chloride. The invention also provides a preparation method of the organic bentonite mixed solid-liquid electrolyte, which comprises the steps of mixing the organic bentonite, the organic solvent and the lithium salt, and then performing physical gelation to obtain the organic bentonite mixed solid-liquid electrolyte. Preferably, the temperature of the physical gelation is 25-60 ℃, and the time of the physical gelation is 3-9 hours. The invention also provides a lithium ion battery, which comprises an anode, a cathode and an electrolyte, wherein the electrolyte is the organic bentonite mixed solid-liquid electrolyte according to the technical scheme. Preferably, the positive electrode comprises a lithium sheet electrode or a sulfur-carbon composite positive electrode, and the negative electrode comprises a lithium sheet electrode or a graphite negative electrode. The invention provides an organic bentonite mixed solid-liquid electrolyte which comprises organic bentonite, an organic solvent and lithium salt, wherein a three-dimensional network structure is formed by interaction of a lamellar layer of t