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CN-122000335-A - Heterojunction type NiO@Fe2O3CC positive electrode material, preparation method and application thereof

CN122000335ACN 122000335 ACN122000335 ACN 122000335ACN-122000335-A

Abstract

The invention relates to the technical field of lithium-oxygen batteries, in particular to a heterojunction type NiO@Fe 2 O 3 /CC positive electrode material, a preparation method and application thereof. According to the invention, a vertically arranged Fe 2 O 3 nano rod array and NiO nano wires attached to the Fe 2 O 3 nano rod array are sequentially constructed on the carbon cloth by a two-step hydrothermal method, so that a unique three-dimensional hierarchical heterostructure is formed, the specific surface area of the material is greatly increased, more active sites are exposed, excellent conductivity and structural stability of the electrode are ensured, the NiO@Fe 2 O 3 p-n heterojunction and the three-dimensional hierarchical structure realize remarkable improvement of the performance of the light-assisted lithium oxygen battery, the overpotential of the battery under the illumination condition is remarkably reduced, the preparation method is simple, precious metals, rare earth or selenide and the like are not depended on, and the excellent electronic conduction path and structural stability are ensured through the direct combination of the carbon cloth substrate and the active material, and the cycle life of the electrode is remarkably prolonged.

Inventors

  • BAI MEI
  • CHEN XIANJIN
  • ZHU PENGHUI
  • ZHANG CHUANJIAN
  • JU SHUYUAN
  • QIN LI
  • HU MIN
  • HE HUAN
  • HUANG HAIXU
  • DING JIANFENG

Assignees

  • 安徽得壹能源科技有限公司

Dates

Publication Date
20260508
Application Date
20260303

Claims (10)

  1. 1. The preparation method of the heterojunction type NiO@Fe 2 O 3 /CC positive electrode material is characterized by comprising the following steps of: dissolving an iron source and a mineralizer in water, adding carbon cloth to perform a first hydrothermal reaction, washing, drying and calcining for the first time after the reaction to obtain Fe 2 O 3 /CC; And (3) dissolving a nickel source and a precipitator in deionized water, adding the obtained Fe 2 O 3 /CC, performing a second hydrothermal reaction, washing, drying and calcining for the second time after the reaction, and thus obtaining the nickel-based alloy.
  2. 2. The method according to claim 1, wherein the iron source is ferric chloride, ferric nitrate or ferric sulfate, or the mineralizer is sodium sulfate, sodium nitrate or sodium chloride.
  3. 3. The method of claim 2, wherein the molar ratio of the iron source to the mineralizer is 1:1-3.
  4. 4. The method according to claim 1, wherein the precipitant is urea or hexamethylenetetramine, or the nickel source is nickel nitrate, nickel chloride or nickel sulfate.
  5. 5. The method of claim 4, wherein the molar ratio of the nickel source to the precipitant is 1:3-6.
  6. 6. The method according to claim 1, wherein the first hydrothermal reaction is carried out at a temperature of 100 to 150 ℃ for 4 to 8 hours, or the first calcination is carried out at a temperature of 300 to 400 ℃ for 1to 3 hours.
  7. 7. The method according to claim 1, wherein the second hydrothermal reaction is carried out at a temperature of 100 to 150 ℃ for 4 to 8 hours, or the second calcination is carried out at a temperature of 300 to 400 ℃ for 1to 3 hours.
  8. 8. The heterojunction type NiO@Fe 2 O 3 /CC positive electrode material prepared by the preparation method according to any one of claims 1-7, preferably, an Fe 2 O 3 nanorod array is vertically grown on carbon cloth fibers, and NiO nanowires are attached to the surface of the Fe 2 O 3 nanorod.
  9. 9. The use of the heterojunction type nio@fe 2 O 3 /CC cathode material as defined in claim 8 in a photo-assisted lithium-oxygen battery cathode.
  10. 10. A photo-assisted lithium-oxygen battery, wherein the positive electrode of the photo-assisted lithium-oxygen battery is the heterojunction type nio@fe 2 O 3 /CC positive electrode material as claimed in claim 8.

Description

Heterojunction type NiO@Fe 2O3/CC positive electrode material and preparation method and application thereof Technical Field The invention relates to the technical field of lithium-oxygen batteries, in particular to a heterojunction type NiO@Fe 2O3/CC positive electrode material, a preparation method and application thereof. Background The charge and discharge process of lithium-oxygen batteries is essentially a process of ORR and OER, and is embodied by the formation and decomposition of Li 2O2. However, li 2O2 itself is poor in conductivity, and the reversible generation and decomposition kinetics are slow, resulting in high charge-discharge overpotential, short cycle life, and low energy efficiency in actual operation. The photo-assisted lithium-oxygen battery technology combines photoelectrocatalysis with electrochemical reaction, utilizes light energy to excite a positive electrode catalyst to generate electron-hole pairs, and photo-generated electrons can promote the generation of Li 2O2 in the ORR process, and photo-generated holes can effectively drive the decomposition of Li 2O2 in the OER process, so that the overpotential is reduced fundamentally. However, materials in the prior art are mostly dependent on noble metals, rare earth or selenide and the like, the preparation process is complex, the electrode structure is mostly made of powder materials, the electrode is required to be formed into films by means of binders, the conductivity and the stability of the electrode are affected, and the efficient separation aspect of photo-generated carriers is still to be promoted. Disclosure of Invention In view of the above, the invention provides a heterojunction type NiO@Fe 2O3/CC positive electrode material, and a preparation method and application thereof. According to the invention, two different semiconductor materials (p-type NiO and n-type Fe 2O3) are compounded, and the separation of photo-generated electron-hole pairs can be obviously promoted by utilizing an internal electric field formed at an interface of the two different semiconductor materials, and the surface electron structure is regulated, so that more active sites are exposed, and the activity of the material is improved. In order to achieve the above object, the present invention is realized by the following technical scheme: in a first aspect, the invention provides a preparation method of a heterojunction type NiO@Fe 2O3/CC positive electrode material, which comprises the following steps: Dissolving an iron source and a mineralizer in water, adding carbon cloth to perform a first hydrothermal reaction, washing, drying and calcining for the first time after the reaction, and forming an Fe 2O3 nano-rod array (Fe 2O3/CC) on the carbon cloth; And (3) dissolving a nickel source and a precipitator in deionized water, adding the obtained Fe 2O3/CC, performing a second hydrothermal reaction, washing, drying and calcining for the second time after the reaction, and thus obtaining the nickel-based alloy. Further, the electrochemical activation treatment is performed in an acidic electrolyte, the applied voltage is 1.5-2.5V, and the treatment time is 0.5-3 min. Further, the iron source is ferric trichloride, ferric nitrate or ferric sulfate. Further, the mineralizer is sodium sulfate, sodium nitrate or sodium chloride. Further, the molar ratio of the iron source to the mineralizer is 1:1-3. The mineralizer selectively adsorbs on the Fe 2O3 crystal face to regulate the directional growth of the mineralizer, and when the dosage is moderate, a regular nano rod array is formed, and when the dosage is too small, the directional growth is insufficient, and when the dosage is too large, the excessive etching or the structural collapse is caused. Further, the temperature of the first hydrothermal reaction is 100-150 ℃ and the time is 4-8 hours. The first hydrothermal temperature influences the nucleation and growth of Fe 2O3 nano rods, the crystallinity is insufficient when the temperature is too low, the nano rods are sparse and short, and the nano rods are too thick and the specific surface area is reduced when the temperature is too high. Further, the first calcination temperature is 300-400 ℃ and the time is 1-3 hours. Further, the nickel source is nickel nitrate, nickel chloride or nickel sulfate. Further, the precipitant is urea or hexamethylenetetramine. Further, the molar ratio of the nickel source to the precipitant is 1:3-6. The usage amount of the precipitant determines the release rate of OH -, ni 2+ is uniformly deposited to form complete coating when the usage amount is moderate, the loading amount is low and the coverage rate is poor when the usage amount is insufficient, niO is agglomerated and the coating is uneven when the usage amount is excessive, and the heterojunction effect can be weakened. Further, the temperature of the second hydrothermal reaction is 100-150 ℃ and the time is 4-8 hours. The hydrothermal temperature for the s