阅读说明：本技术 一种葡萄糖水热碳和氮共掺杂石墨毡电极及其制备方法和应用 (Glucose hydrothermal carbon and nitrogen co-doped graphite felt electrode and preparation method and application thereof ) 是由 谢在来 邱九根 于 2019-09-24 设计创作，主要内容包括：本发明属于电极材料及其制备和应用领域,特别涉及一种葡萄糖水热碳和氮共掺杂石墨毡电极及其制备和应用。本发明以葡萄糖、尿素和碳毡为原料,经过水热和高温煅烧合成葡萄糖水热碳和氮共掺杂的石墨毡复合材料。本发明克服现有技术制备的电极材料循环性能不稳定的技术缺陷,该方法制备的复合电极亲水性好、有效的降低了电子转移电阻,从而提高了VRFB的能量效率和能量输出。(The invention belongs to the field of electrode materials and preparation and application thereof, and particularly relates to a glucose hydrothermal carbon and nitrogen co-doped graphite felt electrode and preparation and application thereof. The invention takes glucose, urea and carbon felt as raw materials, and synthesizes the glucose hydrothermal carbon and nitrogen co-doped graphite felt composite material through hydrothermal and high-temperature calcination. The invention overcomes the technical defect of unstable cycle performance of the electrode material prepared by the prior art, and the composite electrode prepared by the method has good hydrophilicity and effectively reduces the electron transfer resistance, thereby improving the energy efficiency and energy output of VRFB.)

1. A glucose hydrothermal carbon and nitrogen co-doped graphite felt electrode is characterized in that a graphite felt is used as a substrate, and a glucose hydrothermal carbon and nitrogen material is uniformly loaded on the surface of the graphite felt through an in-situ chemical combination method.

2. The preparation method of the glucose hydrothermal carbon and nitrogen co-doped graphite felt according to claim 1, which is characterized by comprising the following specific steps:

(1) cutting the purchased commercial graphite felt into the size of 3cm multiplied by 3 cm;

(2) preparing a certain amount of glucose and urea to obtain a mixed solution;

(3) and adding the graphite felt into the mixed solution, carrying out hydrothermal treatment to obtain the graphite felt loaded with glucose hydrothermal carbon and nitrogen, taking out the graphite felt, filtering and washing the graphite felt by using deionized water, carrying out vacuum drying, and carrying out thermal stabilization to obtain the graphite felt electrode loaded with glucose hydrothermal carbon and nitrogen.

3. The method according to claim 2, wherein the mass of the graphite felt in the step (1) is 0.45 g.

4. The method according to claim 2, wherein the mass ratio of glucose to urea in step (2) is 1: 1.

5. The method according to claim 2, wherein the glucose concentration in the step (2) is 0.021 to 0.083mol/L and the urea concentration is 0.063 to 0.25 mol/L.

6. The method according to claim 2, wherein the hydrothermal treatment temperature in the step (3) is 180 ℃ and the treatment time is 12 hours.

7. The preparation method according to claim 2, wherein the thermal stabilization in step (3) is specifically: placing the graphite felt in a tubular furnace, heating the graphite felt for 2 hours at 1000 ℃ at the heating rate of 10 ℃/min in the nitrogen atmosphere, and taking out the graphite felt after thermal stabilization after the temperature in the tubular furnace is reduced to the room temperature.

8. A glucose hydrothermal carbon and nitrogen co-doped graphite felt electrode prepared by the method of any one of claims 1 ~ 7.

9. Use of the glucose hydrothermal carbon and nitrogen co-doped graphite felt electrode prepared by the method of any one of claims 1 ~ 7 as a positive electrode and a negative electrode of an all vanadium redox flow battery.

Technical Field

The invention belongs to the field of electrode materials and preparation and application thereof, and particularly relates to a glucose hydrothermal carbon and nitrogen co-doped graphite felt electrode and preparation and application thereof.

Background

With the serious damage of the earth's environment caused by the massive exploitation and utilization of fossil fuels on the earth and the limited reserves of fossil resources on the earth, energy shortage and environmental pollution have accelerated the search for renewable energy sources, for example, people have made great progress in the fields of solar energy and wind energy, but the intermittency of solar energy and wind energy has hindered the further development thereof, and m. skylase-Kazacos et al in the middle of 1980 firstly proposed an All-vanadium redox flow battery (m. skylase-Kazacos and r. g.robins, US Pat. 4786567,1986). The all-vanadium redox flow battery has the advantages of high efficiency, strong charge and discharge capacity, long cycle life, low energy storage cost and the like, and M. Rychcik and the like firstly study electrodes of the all-vanadium redox flow battery at the end of 80 s in the 19 th century [ M. Rychcik and M. Skyllas-Kazacos, J. Power sources, 1987,19,45-54], but the current commercial graphite felt still has the defects of poor hydrophilicity, poor cycle stability, low electrochemical activity and the like.

In order to further improve the stability and electrochemical activity of the electrode, extensive research is being conducted on the preparation of electrode materials. Preparing the graphite felt electrode loaded by the carbon sheet at 100 mA/cm by Yu Gao and the like through a standing method^-2An energy efficiency of 81% was obtained at a current density [ Yu Gao, Hongrui Wang, Qiang Ma, Anjun Wu, WeiZhang, Chuanxiang Zhang, Zehua Chen, Xian-Xian Zeng, Xiongwei Wu, Yuping Wu, carbon.2019, 148,9-15]And the energy efficiency is higher than that of the commercial graphite felt under the same condition. The thermal polymerization method adopted by Jiyeon Kim and the like to prepare the N/O co-doped graphite felt improves the electrochemical activity of the graphite felt to a great extent [ Jiyeon Kim, Hyebin Lim, just-Young Juoung, Eun-Sook Lee, Jung S. Yi, Doohwan Lee, carbon.2017, 111,529-]。

Therefore, the carbon material and the nitrogen atom have diversified mechanisms to participate in the electrode reaction of the VRFB, and the energy efficiency and the electrochemical activity of the VRFB can be effectively improved by adopting the graphite felt material loaded with the carbon material and the nitrogen together.

Disclosure of Invention

The invention aims to provide a glucose hydrothermal carbon and nitrogen co-doped graphite felt electrode and preparation and application thereof, and overcomes the technical defect that the electrode material prepared by the prior art is unstable in cycle performance.

In order to achieve the purpose, the invention adopts the following technical scheme:

a glucose hydrothermal carbon and nitrogen co-doped graphite felt electrode is characterized in that a graphite felt is a carbon material in a carbon fiber shape, and glucose hydrothermal carbon and nitrogen are loaded on the surface of the graphite felt through a thermal polymerization method; carbon fiber-like graphite felt is a substrate made with carbon fibers.

A preparation method of a glucose hydrothermal carbon and nitrogen co-doped graphite felt electrode comprises the following specific steps:

(1) commercial graphite felt purchased was cut to a size of 3cm x 3 cm.

(2) Preparing a certain amount of glucose and urea to obtain a mixed solution.

(3) And adding the graphite felt into the mixed solution, carrying out hydrothermal treatment to obtain the graphite felt loaded with glucose hydrothermal carbon and nitrogen, taking out the graphite felt, filtering and washing the graphite felt by using deionized water, carrying out vacuum drying, and carrying out thermal stabilization to obtain the graphite felt electrode loaded with glucose hydrothermal carbon and nitrogen.

Further, the mass of the graphite felt in the step (1) is 0.45 g.

Further, the mass ratio of the glucose to the urea in the step (2) is 1: 1.

Further, in the step (2), the glucose concentration is 0.021-0.083mol/L, and the urea concentration is 0.063-0.25 mol/L.

Further, the proportion of the graphite felt to the mixed solution in the step (3) is 0.45 g: 30 ml.

Further, the hydrothermal treatment temperature in the step (3) is 180 ℃, and the treatment time is 12 h.

Further, the heat stabilization in the step (3) is specifically: placing the graphite felt in a tubular furnace, heating the graphite felt for 2 hours at 1000 ℃ at the heating rate of 10 ℃/min in the nitrogen atmosphere, and taking out the graphite felt after thermal stabilization after the temperature in the tubular furnace is reduced to the room temperature.

The invention provides a carbon and nitrogen co-doped graphite felt electrode for glucose hydrothermal preparation.

The invention also provides application of the glucose hydrothermal carbon and nitrogen co-doped graphite felt electrode as a positive electrode and a negative electrode of VRFB. Wherein VRFB is an all vanadium redox flow battery.

The application specifically comprises the following steps: glucose hydrothermal carbon and nitrogen co-doped graphite felt is used as an electrode, and the anolyte is 1M VO²⁺+ 3M H₂SO₄The catholyte solution was 1M V³⁺ + 3M H₂SO₄The electrolyte was flowed between the electrodes by means of a peristaltic pump and nitrogen was bubbled through the negative electrode to exclude oxygen from the air before starting the test.

The invention has the following remarkable advantages:

compared with the existing commercial graphite felt electrode (Gansu Heheshi carbon fiber Co., Ltd.), the glucose hydrothermal carbon and nitrogen co-doped graphite felt electrode prepared by the invention has the discharge capacity of 200mA/cm when being used as a VRFB electrode^-2The current density of the lithium ion battery can reach 1.4 times of that of a commercial electrode at the highest, and the maximum discharge capacity of the lithium ion battery can reach 335.6 mA. Secondly, the glucose hydrothermal carbon particles are uniformly distributed on the graphite felt, a large number of defects are introduced on the graphite felt, and nitrogen and oxygen functional groups are introduced, wherein the nitrogen content is 1.3%, and the oxygen atom content is increased from 3.04% to 5.55%, so that abundant active sites are provided for electrode reaction.

Drawings

Fig. 1 is a scanning electron microscope image of the glucose hydrothermal carbon and nitrogen co-doped graphite felt prepared by the invention.

Fig. 2 is a graph comparing the energy efficiency of the glucose hydrothermal carbon and nitrogen co-doped graphite felt prepared by the invention with that of a commercial graphite felt.

FIG. 3 is a graph comparing the discharge capacity of the glucose hydrothermal carbon and nitrogen co-doped graphite felt prepared by the invention with that of a commercial graphite felt, wherein a is the discharge capacity under different current densities, and b is 200mA/cm^-2Graph of decay of discharge capacity at current density for 150 cycles.

FIG. 4 is an X-ray photoelectron spectrum of nitrogen atoms.

Detailed Description