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CN-121983578-A - Titanium dioxide/graphene composite material and preparation method and application thereof

CN121983578ACN 121983578 ACN121983578 ACN 121983578ACN-121983578-A

Abstract

The invention belongs to the technical field of battery materials, and particularly relates to a titanium dioxide/graphene composite material, and a preparation method and application thereof. The preparation method of the titanium dioxide/graphene composite material comprises the following steps of S1, adding titanium alkoxide into absolute ethyl alcohol, stirring to form uniform and transparent titanium alkoxide solution, S2, dispersing graphene in pure water in an ultrasonic mode to form uniform graphene dispersion liquid, S3, adding the titanium alkoxide solution into the graphene dispersion liquid in a dropwise mode, stirring to obtain mixed liquid, S4, adding glacial acetic acid into the mixed liquid in a dropwise mode, heating, stirring to form sol, ageing, drying and crushing to obtain composite precursor powder, S5, annealing the composite precursor powder in a nitrogen atmosphere, and cooling to room temperature to obtain the titanium dioxide/graphene composite material. The invention can ensure extremely low electrode internal resistance when applied to batteries, and can effectively inhibit hydrogen evolution side reaction.

Inventors

  • WU JINYANG
  • LIU JIANZHONG
  • LIU SI
  • WEN ZHONGQIANG

Assignees

  • 湖南金阳烯碳新材料股份有限公司

Dates

Publication Date
20260505
Application Date
20260408

Claims (9)

  1. 1. A preparation method of a titanium dioxide/graphene composite material is characterized in that, The method comprises the following steps: S1, adding titanium alkoxide into absolute ethyl alcohol, and stirring to form uniform and transparent titanium alkoxide solution; s2, ultrasonically dispersing the modified three-dimensional porous graphene in pure water to form uniform graphene dispersion liquid; s3, dropwise adding the titanium alkoxide solution obtained in the step S1 into the graphene dispersion liquid obtained in the step S2, and stirring to obtain a mixed solution; S4, dropwise adding glacial acetic acid into the mixed solution in the step S3, heating and stirring to form sol, aging, and drying and crushing to obtain composite precursor powder; s5, annealing the composite precursor powder in the step S4 in a nitrogen atmosphere, and cooling to room temperature to obtain a titanium dioxide/graphene composite material; The preparation method of the modified three-dimensional porous graphene comprises the steps of preparing the three-dimensional porous graphene by taking graphene oxide dispersion liquid and polyvinyl alcohol as raw materials and matching with nitric acid solution, and mixing the three-dimensional porous graphene with cerium chloride heptahydrate for hydrothermal reaction to obtain the modified three-dimensional porous graphene.
  2. 2. The method for preparing the titanium dioxide/graphene composite material according to claim 1, wherein, The stirring time in the step S1 is 10-60 min, the temperature is 25-65 ℃, and the rotating speed is 400-800 rpm; In the step S2, the ultrasonic power of ultrasonic dispersion is 300-400W, and the ultrasonic time is 10-60 min; the stirring treatment in the step S3 is carried out under the conditions that the stirring time is 1-5 h, the stirring temperature is 25-100 ℃, and the stirring rotating speed is 400-800 rpm.
  3. 3. The method for preparing the titanium dioxide/graphene composite material according to claim 1, wherein, The heating and stirring conditions in the step S4 are that the temperature is 25-65 ℃, the time is 1-5 h, the rotating speed is 400-800 rpm, the aging time is 12-48 h, the drying temperature is 50-80 ℃, the power of the crushing pulverizer is 1000-1200W, and the rotating speed is 28000-30000 r/min; The annealing treatment in the step S5 is carried out under the conditions that the temperature rising rate is 3-5 ℃ per minute, the annealing temperature is 200-600 ℃ and the annealing time is 1-5 h.
  4. 4. The method for preparing the titanium dioxide/graphene composite material according to claim 1, wherein, The mass ratio of the titanium alkoxide to the absolute ethyl alcohol is 1 (2-20), the mass ratio of the titanium alkoxide to the graphene is 1 (2-20), the mass ratio of the titanium alkoxide to the glacial acetic acid is 1 (1-5), and the mass ratio of the graphene to the pure water is 1 (10-200).
  5. 5. The method for preparing the titanium dioxide/graphene composite material according to claim 1, wherein, The titanium alkoxide is selected from one or more of tetraisopropyl titanate, tetraethyl titanate and tetrabutyl titanate.
  6. 6. The method for preparing the titanium dioxide/graphene composite material according to claim 1, wherein, The preparation method of the three-dimensional porous graphene comprises the steps of uniformly mixing 400-500 parts of graphene oxide dispersion liquid with the concentration of 1mg/mL and 40-80 parts of polyvinyl alcohol aqueous solution with the concentration of 1mg/mL in parts by weight, freeze-drying to obtain mixed powder, adding 1-2 parts of the mixed powder into 60-80 parts of nitric acid solution with the concentration of 40% by mass, stirring and refluxing for 10-12 hours, centrifuging, washing with deionized water, and vacuum-drying to obtain the three-dimensional porous graphene.
  7. 7. The method for preparing the titanium dioxide/graphene composite material according to claim 1, wherein, The hydrothermal reaction comprises the steps of adding 1-2 parts by weight of the three-dimensional porous graphene into 500-600 parts by weight of deionized water, performing ultrasonic dispersion for 2-4 hours, adding 0.16-0.24 part by weight of cerium chloride heptahydrate, magnetically stirring for 3-5 hours, performing hydrothermal treatment at 120-130 ℃ for 10-12 hours, performing suction filtration, washing with deionized water, and freeze-drying to obtain the modified three-dimensional porous graphene.
  8. 8. The titanium dioxide/graphene composite material is characterized by being prepared by the preparation method according to any one of claims 1-7.
  9. 9. The application of the titanium dioxide/graphene composite material obtained by the preparation method according to any one of claims 1-7 in negative electrode lead plaster.

Description

Titanium dioxide/graphene composite material and preparation method and application thereof Technical Field The invention belongs to the technical field of battery materials, and particularly relates to a titanium dioxide/graphene composite material, and a preparation method and application thereof. Background Lead-acid batteries are one of the longest-history electrochemical energy storage systems, and are still the mainstream choice in the fields of automobile starting power supplies, electric light automobile power sources, industrial energy storage, communication backup power supplies and the like due to the fact that the lead-acid batteries are obvious in cost advantage, high in technical reliability, complete in process and excellent in instant high-current discharge capacity. However, the system can continuously generate serious hydrogen evolution side reaction in long-term circulation, especially under partial charge state or overcharge condition, wherein the hydrogen overpotential of the lead sulfate is lower than that of the metallic lead, a more easily-generated place is provided for hydrogen evolution, and the lead sulfate which exists for a long time can be gradually recrystallized and coarsened to form irreversible sulfation, so that the hydrogen evolution and capacity loss are further aggravated. The hydrogen evolution reaction not only directly causes electric energy loss and reduces charging efficiency, but also causes electrolyte water loss and density imbalance, and the separated hydrogen can damage the structure of a negative electrode active substance under the long-term action, so that the softening and falling of the active substance are aggravated, thereby accelerating capacity attenuation and battery failure, easily causing the reduction of charging efficiency and causing safety risks. Therefore, effective inhibition of hydrogen evolution is a core key technology for improving the comprehensive performance of lead-acid batteries. To address this challenge, methods for adding functional materials to negative electrode lead pastes are commonly employed in the industry, mainly focusing on both carbon materials and metal oxides. The carbon material (such as carbon black, graphene, carbon nano tube and the like) aims to construct a high-conductivity network and solve the problem of poor conductivity of a negative electrode active substance (lead/lead sulfate), so that polarization is reduced, and power performance and charge acceptance are improved. However, many high specific surface area carbon materials, due to their surface characteristics, may instead provide active sites for hydrogen ion reduction, with the potential risk of catalyzing hydrogen evolution. On the other hand, metal oxides (such as ZnO, tiO 2, etc.) have been shown to inhibit hydrogen evolution by changing the electrode surface properties, increasing hydrogen evolution overpotential, etc., but these materials are generally poor in conductivity, and large additions can significantly increase the internal resistance of the electrode, impair the high rate discharge performance of the battery, and form a performance contradiction between "inhibit hydrogen evolution" and "maintain conductivity". In recent years, researchers have tried to combine the two to seek synergy. For example, chinese patent application (publication No. CN113764627 a) discloses a high-performance lead-carbon battery negative electrode lead paste formulation and a preparation method thereof, which adopts graphene and carbon tubes, but the hydrogen suppression mechanism is still mainly dependent on traditional barium sulfate, and the effect is limited. Chinese patent application (publication No. CN 117199344A) discloses a negative electrode lead plaster for inhibiting hydrogen evolution and prolonging the cycle life of a battery and a preparation method thereof, which combines modified graphene and zinc oxide, and has certain performance improvement, but the physical mixing mode is difficult to realize optimal synergy of functional components on nanometer scale, so that oxide agglomeration is often caused to block a conductive path, or a carbon material cannot effectively modify the surface of the oxide, so that the conductivity is improved and the hydrogen evolution inhibition cannot be synchronously maximized, and the synergistic effect is not expected. In summary, the prior art can not fundamentally solve the opposite problem of performance of the carbon material and the metal oxide, and how to develop a novel composite material additive, which can realize accurate and firm combination of a high conductive network and a high dispersion hydrogen suppression active site on a microstructure, so that the hydrogen evolution side reaction is effectively suppressed while the extremely low internal resistance of an electrode is ensured, and the novel composite material additive has an urgent need for promoting the technical upgrading of a lead-acid battery,