Search

CN-122010253-A - Titanium-doped lithium manganate self-supporting electrode and preparation method and application thereof

CN122010253ACN 122010253 ACN122010253 ACN 122010253ACN-122010253-A

Abstract

The invention relates to a titanium doped lithium manganate self-supporting electrode, and a preparation method and application thereof. The self-supporting electrode comprises a porous titanium fiber matrix and a titanium doped lithium manganate nano-sheet active layer which grows on the surface of the porous titanium fiber matrix and in the pore canal in situ, so that an integral conductive self-supporting electrode structure is formed. The lithium manganate is of a spinel structure, titanium element is introduced into a lithium manganate crystal lattice in a doped mode, and the doping mole ratio of the titanium element is 1% -10% of the mole amount of the manganese element. Compared with the prior art, the invention can form an integral conductive structure without a binder, can be applied to a capacitive deionization system, and realizes high-efficiency and selective recovery of lithium ions in lithium-containing solution.

Inventors

  • ZHANG DENGSONG
  • ZHAO YANAN
  • YI QIUYING

Assignees

  • 上海大学

Dates

Publication Date
20260512
Application Date
20260211

Claims (10)

  1. 1. The self-supporting electrode is characterized by comprising a porous titanium fiber matrix and a titanium doped lithium manganate nano-sheet active layer which grows on the surface of the porous titanium fiber matrix and in a pore canal in situ, so that an integral conductive self-supporting electrode structure is formed; the lithium manganate is of a spinel structure, titanium element is introduced into a lithium manganate crystal lattice in a doped mode, and the doping mole ratio of the titanium element is 1% -10% of the mole amount of the manganese element.
  2. 2. The self-supporting electrode of titanium doped lithium manganate of claim 1, wherein the porous titanium fiber matrix is a conductive titanium fiber felt.
  3. 3. The self-supporting electrode of titanium doped lithium manganate according to claim 1, wherein the active layer of titanium doped lithium manganate nanosheets grows continuously along the surface of the metal fibers; the shape of the titanium doped lithium manganate nano-sheet active layer is sheet, plate or lamellar; The size of the lithium manganate nano-sheet is 100-300 nm.
  4. 4. A method for preparing the titanium-doped lithium manganate self-supporting electrode according to any one of claims 1-3, wherein the preparation method comprises the following steps: S1, carrying out surface treatment on a porous titanium fiber matrix by using oxalic acid solution; S2, preparing a manganese source, urea and ammonium fluoride into a precursor solution, and placing the porous titanium fiber matrix pretreated in the S1 into the precursor solution for hydrothermal reaction to enable a manganese-containing precursor and titanium element to deposit and grow on the surface of the porous titanium fiber matrix and inside the pore canal; S3, performing heat treatment on the porous titanium fiber matrix obtained in the step S2 to form a titanium doped manganese oxide layer; and S4, placing the porous titanium fiber matrix treated in the step S3 into a lithium source solution for hydrothermal reaction, and finally obtaining the titanium-doped lithium manganate self-supporting electrode.
  5. 5. The method for preparing a titanium-doped lithium manganate self-supporting electrode according to claim 1, wherein in the step S1, the mass fraction of the oxalic acid solution is 5% -8%; the surface treatment temperature is 80-90 ℃.
  6. 6. The method for preparing a titanium-doped lithium manganate self-supporting electrode according to claim 1, wherein in the step S2, the manganese source is any one or more of manganese nitrate tetrahydrate, manganese sulfate and manganese chloride; the mass ratio of the manganese source to the urea to the ammonium fluoride is (0.1-0.6) (0.05-0.3); the temperature of the hydrothermal reaction is 100-150 ℃, and the time of the hydrothermal reaction is 2-10 h.
  7. 7. The method for preparing a self-supporting electrode of titanium-doped lithium manganate according to claim 1, wherein in step S3, the heat treatment is performed in a muffle furnace; The temperature of the heat treatment is 200-400 ℃.
  8. 8. The method for preparing a self-supporting electrode of titanium-doped lithium manganate according to claim 1, wherein in the step S4, the lithium source is any one or more of lithium hydroxide monohydrate, lithium carbonate and lithium chloride; The concentration of the lithium source is 10-50 mmol/L; The temperature of the hydrothermal reaction is 180-220 ℃, and the time of the hydrothermal reaction is 15-24 h.
  9. 9. Use of the self-supporting electrode of titanium doped lithium manganate in any one of claims 1-3 in a capacitive deionization system, wherein the self-supporting electrode of titanium doped lithium manganate is used as a capacitive deionization working electrode for selectively intercalating and releasing lithium ions in a lithium-containing solution under the action of an external electric field to realize enrichment and recovery of lithium ions.
  10. 10. The use of a titanium doped lithium manganate self supporting electrode according to claim 9 in a capacitive deionization system, wherein the lithium containing solution includes, but is not limited to, salt lake brine; The capacitive deionization system adopts a fluid penetrating operation mode, so that a lithium-containing solution flows along the three-dimensional pore path direction of the titanium-doped lithium manganate self-supporting electrode.

Description

Titanium-doped lithium manganate self-supporting electrode and preparation method and application thereof Technical Field The invention relates to the technical field of water treatment, in particular to a titanium doped lithium manganate self-supporting electrode and a preparation method and application thereof. Background The lithium resource is used as an important basic material in new energy industry and strategically emerging industry, and is widely applied to the fields of lithium ion batteries, energy storage systems, novel electronic devices and the like. With the rapid development of new energy automobiles and large-scale energy storage technologies, the demand of lithium resources is continuously increased, and the traditional lithium resource supply mode faces the problems of lower resource grade, higher development cost and the like. Salt lake brine is considered as one of important lithium resource sources because of its abundant reserves and concentrated distribution. However, the content of lithium ions in salt lake brine is generally low, and high-concentration magnesium ions, sodium ions, calcium ions and other coexisting ions are often accompanied, so that the ion composition is complex, and great challenges are brought to the efficient separation and recovery of lithium resources. At present, the technology for extracting lithium from salt lake brine mainly comprises a precipitation method, a solvent extraction method, an adsorption method, a membrane separation method and the like. The precipitation method and the solvent extraction method have complex flow, high medicament consumption and heavy environmental burden, and the membrane separation method is easy to cause membrane pollution and performance attenuation in a high-salt system. In contrast, the capacitive deionization technology based on the electrochemical principle is gradually focused on the advantages of low energy consumption, mild operation conditions, good reproducibility and the like, and is explored to be used for selectively separating and recovering lithium ions in salt lake brine. In a capacitive deionization lithium extraction system, electrode materials are key factors determining separation efficiency and operation stability. The lithium manganate material has reversible lithium intercalation and deintercalation sites in a crystal structure, and can realize selective intercalation and deintercalation of lithium ions under the action of an external electric field, so that the lithium manganate material is widely studied as a capacitor deionized lithium extraction electrode material. As CN120250082a discloses a lithium iron phosphate-composite lithium manganate composite material for extracting lithium from high-altitude salt lake, spinel-type and layered lithium manganate are compounded in lithium iron phosphate to form a lithium iron phosphate-composite lithium manganate material, so as to solve the problem of difficult migration of lithium ions in the lithium extraction from high-altitude salt lake. However, the above scheme still adopts a form that the composite lithium manganate powder material is loaded on the surface of the current collector after being compounded with the conductive agent and the binder, and has the problems of limited utilization rate of active substances, longer ion transmission path, insufficient structural stability in the circulating process and the like, and capacity attenuation and performance reduction are easy to occur under a complex salt lake brine system. In addition, the existing capacitive deionization device mostly adopts a working mode that fluid flows in parallel along the surface of an electrode, the contact between electrolyte and an electrode active layer is limited, active sites inside the electrode are difficult to fully utilize, and the improvement of lithium ion separation efficiency is further restricted. Therefore, how to improve the structural stability, the utilization efficiency of active sites and the effective contact degree between the electrolyte and the electrode of the lithium manganate electrode through electrode structural design and material modification is still a technical problem to be solved in the field of salt lake brine capacitive deionization lithium extraction. Disclosure of Invention The invention aims to overcome at least one defect in the prior art and provide a titanium doped lithium manganate self-supporting electrode, and a preparation method and application thereof. The aim of the invention can be achieved by the following technical scheme: the invention firstly provides a titanium doped lithium manganate self-supporting electrode, which comprises a porous titanium fiber matrix and a titanium doped lithium manganate nano-sheet active layer which grows on the surface of the porous titanium fiber matrix and in a pore canal in situ to form an integral conductive self-supporting electrode structure; the lithium manganate is of a spinel struc