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CN-121974330-A - Tungsten carbide modified hard carbon material, preparation method and application thereof, and battery

CN121974330ACN 121974330 ACN121974330 ACN 121974330ACN-121974330-A

Abstract

The invention provides a tungsten carbide modified hard carbon material, a preparation method and application thereof, and a battery. The preparation method comprises the steps of pre-carbonizing a biomass precursor, mixing the biomass precursor with phosphotungstic acid and a solvent to obtain a mixture, carrying out hydrothermal treatment on the mixture, and carbonizing the mixture to obtain the tungsten carbide modified hard carbon material. The preparation method is simple, low in cost and suitable for industrial production, and the prepared tungsten carbide modified hard carbon material has excellent electrochemical performance when applied to batteries, has higher capacity and initial effect, has higher cycle capacity retention rate, and has excellent performance in high-rate low-temperature sodium storage application.

Inventors

  • ZHOU CE
  • WANG LINLIN
  • GONG SIYUAN

Assignees

  • 北京钠谛科技有限公司

Dates

Publication Date
20260505
Application Date
20260311

Claims (10)

  1. 1. The preparation method of the tungsten carbide modified hard carbon material is characterized by comprising the following steps of: Pre-carbonizing a biomass precursor, mixing the biomass precursor with phosphotungstic acid and a solvent to obtain a mixture, carrying out hydrothermal treatment on the mixture, and carbonizing the mixture to obtain the tungsten carbide modified hard carbon material.
  2. 2. The method of producing a tungsten carbide modified hard carbon material according to claim 1, wherein the method of producing satisfies one or more of the following conditions: (1) The biomass precursor comprises one or more of bamboo powder, cotton, wood, straw and straw; (2) The pre-carbonization temperature is 200-400 ℃, e.g., 230 ℃, 250 ℃, 280 ℃, 300 ℃, 320 ℃, 350 ℃, or 380 ℃; (3) The pre-carbonization time is 1-6 hours, for example 2 hours, 3 hours, 4 hours or 5 hours.
  3. 3. The method of producing a tungsten carbide modified hard carbon material according to claim 1, wherein the method of producing satisfies one or more of the following conditions: (1) In the process of mixing the biomass precursor with the phosphotungstic acid and the solvent, the mixing sequence is that the pre-carbonized biomass precursor is firstly dispersed into the solvent, and then the phosphotungstic acid is added; (2) The ratio of the mass of the biomass precursor to the volume of the solvent is 1 (10-50) g/mL; (3) The mass ratio of the phosphotungstic acid to the biomass precursor is 0.02-0.5.
  4. 4. The method of producing a tungsten carbide modified hard carbon material according to claim 1, wherein the method of producing satisfies one or more of the following conditions: (1) The temperature of the hydrothermal treatment is 100-180 ℃, e.g., 110 ℃, 120 ℃, 130 ℃, 140 ℃, 145 ℃, 150 ℃, or 160 ℃; (2) The hydrothermal treatment time is 1-8h, such as 2h, 3h, 4h, 5h or 6h; (3) The carbonization temperature is 900-1600 ℃, e.g., 1000 ℃, 1100 ℃, 1200 ℃, 1300 ℃, 1400 ℃, 1500 ℃, or 1600 ℃; (4) The carbonization time is 1-8h, for example 2h, 3h, 4h or 6h.
  5. 5. The method for preparing a tungsten carbide modified hard carbon material according to claim 1, wherein ball milling is further required after the pre-carbonization and before the mixing of the phosphotungstic acid and the solvent; In the ball milling process, the ball material ratio is preferably (5-15): 1, the ball milling rotating speed is preferably 200-600r/min, and the ball milling time is preferably 2-24h.
  6. 6. A tungsten carbide modified hard carbon material prepared by the method for preparing a tungsten carbide modified hard carbon material according to any one of claims 1 to 5.
  7. 7. The tungsten carbide modified hard carbon material is characterized by comprising an amorphous carbon matrix, a graphite-like boundary layer and tungsten carbide nano particles.
  8. 8. The tungsten carbide modified hard carbon material of claim 7, wherein the graphite-like boundary layer is located between the tungsten carbide nanoparticles and the amorphous carbon matrix; and/or the A D1 /A G ratio of the tungsten carbide modified hard carbon material is 2.7-2.9.
  9. 9. Use of a tungsten carbide modified hard carbon material according to any of claims 6-8 in a battery.
  10. 10. A battery comprising a positive electrode sheet, a negative electrode sheet, and an electrolyte, the negative electrode sheet comprising the tungsten carbide modified hard carbon material of any one of claims 6-8.

Description

Tungsten carbide modified hard carbon material, preparation method and application thereof, and battery Technical Field The invention particularly relates to a tungsten carbide modified hard carbon material, a preparation method and application thereof, and a battery. Background Under the background of the global energy structure to clean and low-carbonization transformation, the electrochemical energy storage technology is used as a core support for new energy grid connection, distributed energy storage and smart grid construction, and the development of the electrochemical energy storage technology is paid attention to. The sodium ion battery has potential application prospect in the field of large-scale electrochemical energy storage (such as photovoltaic, wind power matched energy storage, power grid peak shaving and the like) by virtue of the cost advantages and excellent resource sustainability of raw materials (such as abundant sodium resource reserves, wide distribution and no need of depending on scarce lithium resources), and is expected to become an important supplement or even replacement scheme of the lithium ion battery in a medium-large energy storage scene. The key point of realizing breakthrough improvement of the performance of the sodium ion battery is that the research and development and innovation of the advanced negative electrode material are carried out, and the overall performance and the industrialization feasibility of the battery are directly determined by the sodium storage performance, the stability and the cost of the negative electrode material. Among the negative electrode materials of sodium ion batteries, the hard carbon material has excellent electrochemical performance (high specific capacity, good cycle stability, proper interlayer spacing), simple and easy large-scale synthesis process, low raw material cost and microstructure (pore structure, layered structure and the like) which can be finely optimized by regulating and controlling preparation parameters, becomes a research hot spot in the field of the current negative electrode materials of sodium ion batteries, and has wide application potential in the process of converting laboratory research and development into industrial mass production, and is considered as one of the negative electrode materials of sodium ion batteries with the most industrialization prospect. The hard carbon precursor has wide sources and mainly comprises biomass, resin and the like. Among these, biomass is particularly attractive in large-scale production due to its renewable nature, low cost advantage, and natural designable carbon skeleton structure. However, the current biomass-derived hard carbon still faces a plurality of key bottlenecks, such as limited sodium storage sites caused by insufficient closed cell structures, slow sodium ion transmission kinetics, restriction of rate performance, reduction of electrochemical stability in low-temperature environment and the like, and severely restricts further practical application of the biomass-derived hard carbon. The dynamic performance of the carbon-based material can be effectively improved by metal doping, but the existing research is mostly based on commercial activated carbon or polysaccharide precursors, and the obtained conclusion is difficult to directly migrate to a biomass-derived carbon system with a more complex structure, and the performance bottleneck faced by biomass-derived hard carbon cannot be effectively solved. The low-cost renewable biomass carbon material is used as a key core material for promoting the industrialization process of the sodium ion battery, and the breakthrough of the performance of the biomass carbon material is directly related to the competitiveness and the application prospect of the sodium ion battery in the large-scale energy storage field. Therefore, the development of a metal doping strategy suitable for biomass derived carbon has important theoretical significance and practical application value for promoting the industrialized application of sodium ion batteries, reducing the cost of large-scale energy storage and assisting global energy transformation. Disclosure of Invention Aiming at the defects of the prior preparation technology, the invention provides a tungsten carbide modified hard carbon material, and a preparation method, application and a battery thereof. The preparation method is simple, low in cost and suitable for industrial production, and the prepared tungsten carbide modified hard carbon material has excellent electrochemical performance when applied to batteries, has higher capacity and initial effect, has higher cycle capacity retention rate, and has excellent performance in high-rate low-temperature sodium storage application. According to the invention, tungsten carbide (WC) crystal domains are selectively generated in a carbon matrix (such as bamboo powder) through hydrothermal anchoring of phosphotungstic acid and W-C