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Technology Development | Subversive Achievements of Professor Hu Xiaojun of Zhejiang University of Technology

Technology Development | Subversive Achievements of Professor Hu Xiaojun of Zhejiang University of Technology

Apr 27,2022

The team of Professor Hu Xiaojun of Zhejiang University of Technology innovatively "restored" the growth process of chemical vapor deposition diamond, and realized the point "stone" into "drill" under low pressure, which provided a new strategy and theoretical basis for the synthesis of large-area diamond. When it comes to diamonds, many people first think of dazzling diamonds. In fact, the application of synthetic diamond in industrial production is also "dazzling". It has all the excellent properties of natural diamonds and is widely used in precision cutting tools, wear-resistant devices, semiconductors and electronic devices, low magnetic detection, biomedicine and so on. At present, there are two main types of industrial synthesis of synthetic diamond: high pressure and high temperature method and chemical vapor deposition method. However, due to the limitation of high temperature and high pressure equipment, it is still difficult to prepare large-size single crystal diamond; chemical vapor deposition needs to grow single crystal diamond with natural single crystal diamond as the substrate, and natural single crystal diamond is limited by area, still can not prepare large-area diamond, which greatly limits the application of artificial diamond. The team of Professor Hu Xiaojun of Zhejiang University of Technology has long focused on the research work of diamond films and nano-carbon materials, and is committed to exploring the preparation, doping new methods and photoelectric properties of diamond films and other materials. The research team is concerned that compared with graphite, the thermodynamically metastable diamond can be formed under the low pressure of chemical vapor deposition, and its unique formation mechanism may contain a way to synthesize large-area diamond. However, the growth environment of chemical vapor deposition is complex and it is difficult to achieve in-situ characterization, so the formation mechanism of diamond in the deposition process has always been a difficult problem for scientists in the field of materials. Hu Xiaojun's team used the slow growth method to "restore" the growth process of chemical vapor deposition diamond. The team used "cauliflower"-shaped nano-diamond particles as templates and adopted a series of short-term growth strategies to form instantaneous thin layers. Through direct observation of scanning electron microscopy, Raman spectroscopy and high-resolution transmission electron microscopy, the surface morphology and microstructure of a series of thin layers grown on the "cauliflower"-shaped template at short intervals of 30 seconds at a growth power of 1800 watts were obtained, it was found that the nano-diamond matrix-the initial growth of erect graphene-the growth of erect graphene-the bending of erect graphene into needle-like graphite-the disappearance of needle-like graphite-the recovery of the nano-diamond matrix cycle. This is the first time that the cyclic appearance of graphite/diamond has been found in the chemical vapor deposition process. So how does this process occur? One conjecture is that graphite and diamond grow in turn, and the diamond is covered with graphite after it grows; if so, a large amount of graphite should still be observed in the Raman spectrum after diamond formation, but the actual situation is that the Raman characteristics of the sample are typical of nanodiamond films; To further confirm this never-before-reported phenomenon and the bold conjecture that graphite turns into diamond, the team reduced the growth power to 1600 watts and extended the growth time to 12 minutes to slow the growth rate to capture clearer evidence of graphite turning into diamond. In the 4-minute sample, the main component is relatively straight graphene (Fig. 4b), which changes to graphite nanoneedles (Fig. 4d) at 8 minutes. This nanoneedle contains both graphite (002) and diamond (111) facets (Fig. 4d). When the time was extended to 12 minutes, the graphite disappeared completely, and a large number of diamond grains were observed in the sample (Fig. 4f), indicating that the graphite had been completely converted into diamond. This indicates that the 8 min sample with both diamond (111) and graphite (002) crystal planes is an intermediate transition state for the conversion of graphite to diamond. Further analysis of the structural evolution of this transition state (Figure 4g) shows that graphite (002) is found in the head region 1 of the sample in 8 minutes, a new and darker diamond crystal plane (0.21 nm) appears in the middle region 2 covering the graphite (002) crystal lattice, and the diamond crystal plane (0.21 nm) in the middle region 3 enhances the graphite (002) to weaken, in the root region 4, the graphite (002) lattice disappears and the diamond (0.21 nm) lattice becomes the host lattice. This clearly demonstrates the gradual conversion of graphite to diamond, as shown in Schemes 4j and j-1. It can be seen that in the process of chemical vapor deposition, the formation of diamond is from the phase change of graphite, which subverts the traditional concepts of "active carbon atoms piled up into sp3 diamond lattice" and "sp2 graphite carbon phase is the 'carbon rubbish' in the growth process of diamond film, which is removed by hydrogen etching in the atmosphere.

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"Visiting Enterprises to Tougang" Entering New District, "School-land Cooperation" Promoting Employment! Wanxin Graphite Valley Attends Online Docking Meeting between New District and Harbin Normal University

"Visiting Enterprises to Tougang" Entering New District, "School-land Cooperation" Promoting Employment! Wanxin Graphite Valley Attends Online Docking Meeting between New District and Harbin Normal University

Apr 30,2022

On the afternoon of April 29, Harbin Wanxin Graphite Valley Technology Co., Ltd. participated in the 44th issue of the school-land cooperation online docking meeting jointly organized by Harbin New District Party Working Committee, Harbin New District Management Committee and Harbin Normal University on Friday, focusing on the theme of "visiting enterprises to expand their posts" and "school-land cooperation" to promote employment. Member of the Party Working Committee of Harbin New Area, Member of the Party Working Committee of the Harbin Area of the Free Trade Zone, Wan Bingrui, Member of the Standing Committee of the Songbei District Committee and Minister of the Organization Department, Yu Hong, Director of the Development and Reform Bureau of Harbin New Area, Guo Li, Deputy Secretary of the Party Committee and Chairman of the Labor Union of Harbin Normal University And relevant college heads attended the meeting. Wanxin Graphite Valley with Zhongke Yingjiang, University of Technology Software, Gushi Biology, Hailingke, Chaoxi Wenchuang and other 6 enterprises to participate in the meeting. The meeting was presided over by Cheng Huaiqiang, general manager of Harbin New District Human Resources Service Co., Ltd. At the meeting, Wan Bingrui, member of the Standing Committee of the Songbei District Party Committee and Minister of the Organization Department, first introduced the overall development of the Harbin New District and the various talent policies and implementation of the New District. Minister Wan said that in recent years, Harbin New area has a strong momentum of development and is in a period of historical opportunity of "superposition of five districts." the demand for talents in the development of enterprises is more urgent than ever before, and college graduates will get a broad space for development in the new area. It is hoped that through today's activities, Harbin Normal University can find cooperative enterprises suitable for students' internship and employment, and graduates can get more opportunities to display their talents and let more outstanding talents stay in the new area. In the school promotion session, Guo Li, deputy secretary of the Party Committee of Harbin Normal University, first introduced the school's general situation and student source information to the leaders of the new district and corporate guests attending the meeting. Secretary Guo said that there are nearly 10,000 graduates of the 2022 class of Harbin Normal University. Harbin New District is an important area for normal university graduates to stay in the province for employment. He hopes to further build a cooperation platform, establish a benign interaction mechanism, and carry out pragmatic, efficient and long-term in-depth docking., Give full play to the advantages of school-local, school-enterprise cooperation, and carry out more extensive, in-depth and lasting cooperation in talent training, internship, innovation and entrepreneurship. After the introduction of Secretary Guo, Zhou Guohui, Dean of the School of Computer Science and Information Engineering of Harbin Normal University, Chang Weidong, Secretary of the Party Committee of the School of Chemistry and Chemical Engineering, Deng Tienan, Secretary of the Party Committee of the School of Management, Si Hong, Secretary of the Party Committee of the Academy of Fine Arts, and Yang Shoubin, Secretary of the Party Committee of the School of Media, respectively introduced The overall situation of each college, the data of each major graduates, the data, the results, awards, professional settings and resource advantages. In the enterprise promotion link, Harbin Wanxin Graphite Valley Technology Co., Ltd., together with the other five enterprises, made a detailed introduction to the development situation, employment demand, salary and welfare treatment and talent training plan of their respective enterprises. At the meeting, Wanxin Graphite Valley made it clear that it is willing to provide interns and fresh graduates with well-paid jobs and internship and practice opportunities, especially technical research and development and marketing positions, so as to jointly develop a mutually beneficial and win-win situation for school-enterprise cooperation. At the end of the meeting, both schools and enterprises expressed their great expectation for offline docking activities after the stabilization of the epidemic, and thanked the new district for schools and enterprises to bridge the issue of enterprises during the epidemic to solve the urgent need for talent and graduates internship employment difficulties.

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Warmly welcome the leaders of Tieling County to visit Shimo Valley Industry Group

Warmly welcome the leaders of Tieling County to visit Shimo Valley Industry Group

May 27,2022

On the morning of May 25, 2022, Sun Zhonghai, deputy head of Tieling County, led a team to visit Graphite Valley Industry Group, accompanied by Executive Deputy General Manager Mei Jia. The two sides had in-depth discussions on the development of Graphite Valley, artificial graphite projects and other topics. As the Tieling County delegation moved to the meeting room, Executive Deputy General Manager Mei Jia introduced the development history, industry overview, and enterprise situation of the Graphite Valley Industry Group, which was highly recognized by the Tieling County delegation. During the negotiation process, the relevant leaders of Tieling County showed great interest in the artificial graphite project, and said that as a leading company rooted in the graphite, graphene and other new carbon material industries, Graphite Valley Industry Group is on the same front as Tieling County. His teammates hope that the two parties can cooperate in depth in the graphite industry in the future and contribute to the development of the graphite industry. After the negotiation, Executive Deputy General Manager Mei Jia led the Tieling County delegation to visit the Graphite (ene) New Materials Research Institute, Graphite Science and Technology Exhibition Hall and Digital Workshop. During the visit, the two sides talked about achievements, innovation and development, and further unified opinions. Mei Jia said that the Graphite Valley Industry Group has entered a period of rapid development and has determined the strategic goal of "one small step a year, one big step in three years, and five years on the platform to build a tens of billions of listed companies. In the future, Graphite Valley Industry Group will build and build a complete ecological blockchain for the graphite (ene) new material industry through industrial layout, technological innovation, and combined with the capital market, promote industry development, create industrial highlands, grasp development opportunities, and adhere to innovation leadership. Determined to become a leader in the new energy and new material industries, to promote the rapid and healthy development of strategic emerging industries and contribute to the sustainable economic and social development. Wang Zhuo, director of Tieling County Project Service Center, Zhao Xueqiang, Secretary of the Party Committee of Shuangjingzi Town, Tieling County, and Gao Fei, deputy mayor of Shuangjingzi Town, Tieling County, participated in the event.

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New process uses CO to produce high-quality graphene at lower cost and faster production

New process uses CO to produce high-quality graphene at lower cost and faster production

May 30,2022

Russian researchers have proposed the first graphene synthesis technology using carbon monoxide as a carbon source. This is a fast and cheap method for producing high-quality graphene. The equipment is relatively simple and can be used in electronic circuits, gas sensors, optics and other fields. The research was conducted by scientists from Skolkovo Science and Technology (Skoltech), Moscow Institute of Physics and Technology (MIPT), Institute of Solid State Physics of the Russian Academy of Sciences, Aalto University and other institutions. The research has been published in the prestigious journal Advanced Science. Chemical vapor deposition (CVD) is the standard technique for synthesizing graphene, which is a honeycomb-arranged single-atom-thick sheet of carbon atoms with unparalleled performance and can be used in electronic applications. CVD generally involves the separation of carbon atoms from gas molecules and their deposition in a monomolecular layer on a substrate in a vacuum chamber. Copper is a commonly used substrate, and the gases used have been hydrocarbons: methane, propane, acetylene, spirits, etc. "The idea of synthesizing graphene from carbon monoxide came up a long time ago, because carbon monoxide is one of the most convenient carbon sources for growing single-walled carbon nanotubes. We have nearly 20 years experience working with carbon monoxide. However, the first experiments with graphene were not successful, and it took us a long time to understand how to control the nucleation and growth of graphene. The beauty of carbon monoxide is the complete catalytic decomposition, which allows us to achieve self-limiting synthesis of single-layer graphene large crystals under ambient pressure." Skoltech Professor Albert Nasibulin, the study's lead researcher, said. "This project is one of the outstanding examples of how basic research can benefit applied technology. As the understanding of the deep-level kinetic mechanism of graphene formation and growth is verified both theoretically and experimentally, optimal conditions for the formation of large graphene crystals become feasible," emphasizes Krasnikov Dmitry, a co-author of the paper and a senior research scientist in Skoltech. The new approach benefits from the so-called self-limiting principle. At high temperatures, when carbon monoxide molecules approach the copper matrix, they tend to decompose into carbon atoms and oxygen atoms. However, once the first layer of crystalline carbon is deposited and separates the gas from the substrate, this tendency subsides, so this process naturally favors the formation of a monolayer. Methane-based CVD can also operate in a self-limiting manner, but to a lesser extent. Grebenko Artem of Skoltech, the first author of the research paper, said, "The system we used has many advantages: the resulting graphene is purer, grows faster and forms better crystals. In addition, by completely excluding hydrogen and other explosive gases from the production process, this improvement can prevent accidents." The fact that this method eliminates the risk of combustion means that no vacuum is required. The equipment works at standard pressure, making it much simpler than traditional CVD equipment. The simplified design in turn leads to faster synthesis. Grebenko said: "From taking a piece of bare copper to pulling out graphene, it only takes 30 minutes." Since the vacuum is no longer required, the equipment not only works faster, but also becomes cheaper. The researchers emphasize that "once you give up the high-end hardware that produces ultra-high vacuum, you can actually assemble our 'garage solvation' for no more than $1000." The researchers also emphasize the high quality of the final material: "Whenever a new graphene synthesis technique is proposed, researchers must prove that it produces the effects they claim. After rigorous testing, we can confidently say that we are indeed high-grade graphene, which can compete with materials produced by CVD from other gases. The resulting material is crystalline, pure, and can be large enough for electronics.

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Graphene modified diaphragm eliminates local temperature hot spots and stabilizes lithium metal anode

Graphene modified diaphragm eliminates local temperature hot spots and stabilizes lithium metal anode

May 30,2022

Lithium-ion battery is an advanced electrochemical energy storage technology for portable electronic devices and electric vehicles. However, the traditional lithium-ion battery with graphite as the negative electrode has a low specific capacity and energy density is close to the limit, which makes it difficult to meet the demand for high energy density secondary batteries. Lithium metal anode is regarded as a very competitive candidate material for achieving high energy density secondary batteries due to its ultra-high theoretical specific energy and lowest electrochemical potential. However, in the actual situation, lithium metal due to its high electrochemical activity and tend to dendrite morphology of uneven deposition characteristics will greatly shorten the service life of the battery, resulting in thermal runaway and other safety issues. Recently, Professor Tang Wei's team from the School of Chemical Engineering of Xi 'an Jiaotong University, Professor Liu Zhaolin from Singapore's A * STAR Institute of Materials Engineering, and Xie Jingying, chief researcher of Shanghai Space Power Research Institute, established a heat transfer-electrochemical deposition coupling model to investigate the space-time evolution of heating power, temperature and lithium ion distribution of lithium deposition system under different deposition currents and overpotentials. The model results show that there are local temperature hot spots at the tips of lithium dendrites, and the existence of local hot spots aggravates the uneven local lithium deposition, which further promotes the growth of lithium dendrites. By introducing graphene sheet coating diaphragm as an in-situ thermal dispersion medium to eliminate local temperature hot spots, the growth of dendrites can be effectively inhibited, and uniform and dense deposition morphology and efficient and stable cycle can be achieved. The composite diaphragm lithium-copper half-cell achieves a stable cycle of 95% coulombic efficiency and more than 240 cycles at a current density of 1 mA cm-2. The lithium metal electrode cycled under the regular PP diaphragm can be "restored" by the composite diaphragm to a stable and efficient cycle with a coulomb efficiency of more than 95% and a more uniform lithium deposition morphology after the cycle coulomb efficiency is reduced to about 60%. In addition, the composite separator achieves stable cycling, high capacity retention and "recovery" characteristics in a Li | | NCM811 battery with a 30.06 mg cm-2 ultra-high load cathode (3.3 low N/P ratio). The article was published in the top international journal Advanced Energy Materials. 1. Simulation of thermodynamic properties of lithium deposition The coupled heat transfer-electrochemical deposition model reveals the local temperature hot spots of the uneven lithium deposition tip under different deposition overpotentials and current densities. The original defects on the surface of the lithium metal electrode lead to non-uniform distribution of the electric field, causing local concentration of lithium ion flux and large reaction current density, resulting in preferential deposition of lithium ions in the tip region and accompanied by ultra-high heat generation rate. The high rate of heat generation and the low thermal conductivity of conventional liquid electrolytes and polymer separators result in significant localized temperature hotspots at the dendrite tips. 2. High thermal conductivity composite diaphragm Excellent single-layer/few-layer graphene dispersion can be obtained by electrochemical exfoliation method and a composite membrane with layered stacked graphene layers covering commercial membranes can be obtained by simple vacuum filtration method. The ion transport characteristics and mechanical strength of the composite separator remain good compared to the original separator, and the wettability and in-plane thermal conductivity are greatly improved. 3. Lithium deposition characteristics and electrochemical performance The structural characteristics of the commercial PP separator and the original defects on the electrode surface cause the lithium deposition to tend to form dendrites and generate local temperature hot spots, which in turn accelerate the aggregation of lithium ions at the tip of the dendrite lithium deposition to further intensify the growth of lithium dendrites. The high thermal conductivity graphene layer on the surface of the composite diaphragm can spread the accumulated heat in time, effectively avoiding the deterioration of dendrites. A large number of irregular dendritic lithium deposits were observed on the surface of the copper current collector after cycling of the blank separator half-cell. In contrast, the composite separator half-cell achieved a relatively uniform deposition morphology. Therefore, the composite separator battery can achieve long cycle stability of more than 240 weeks at a current density of 1 mA cm-2, with a CE of more than 95%. In addition, the lithium metal electrode with degraded performance after cycling under the blank separator can "recover" to better surface morphology and cycling stability under the composite separator. 4. Full battery performance of lithium metal batteries The effectiveness of the high thermal conductivity diaphragm to eliminate local temperature hot spots to suppress lithium dendrites was further verified by the NCM811 full battery. The composite separator not only achieves more stable cycling and capacity retention in regular surface load positive electrode batteries, but also achieves better capacity retention and "recovery" characteristics when matched with an ultra-high surface capacity positive electrode of 30.06 mg cm-2(3.3 low N/P ratio). The evolution of heat generation rate around lithium dendrites and its relationship with local dendrite growth were investigated based on a coupled electrochemical deposition-heat transfer model. Local rapid electrochemical deposition can easily lead to the accumulation of heat and the generation of temperature hot spots, which leads to the subsequent rapid growth of lithium dendrites, which in turn forms a more serious hot spot problem. The introduction of high thermal conductivity graphene layer on the surface of the diaphragm as an in-situ thermal diffusion medium can effectively eliminate the temperature hot spot, resolve the potential risk of rapid deterioration of dendrites, and obtain a more uniform lithium deposition morphology and stable and efficient electrochemical performance. This study provides a unique thermodynamic perspective for the in-depth understanding of the growth and evolution of lithium dendrites, and paves the way for the effective protection of lithium metal anodes and the practical application of lithium metal secondary batteries.

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Strong feelings of rice dumplings warm people's hearts, graphite valley for all employees to distribute Dragon Boat Festival benefits!

Strong feelings of rice dumplings warm people's hearts, graphite valley for all employees to distribute Dragon Boat Festival benefits!

Jun 01,2022

As the Dragon Boat Festival is approaching, in order to thank all employees for their hard work for the company's development, on May 31, Graphite Valley issued Dragon Boat Festival benefits to all employees, making employees deeply feel the care and warmth of the Graphite Valley family. Welfare distribution site, we cooperate with each other, carrying, distribution, distribution...... the scene from time to time bursts of laughter, everywhere is permeated with the atmosphere of joy. Colleagues from various departments went to the scene to collect the zongzi gift box in an orderly manner. Boxes of Duanyang gift boxes full of the company's care and blessings "rushed" to various positions and passed on to every employee. The company was permeated with a warm and harmonious festive atmosphere. A zongzi, a care, zongzi brings not only the enjoyment of taste, but also a good blessing! The joy of the employees who received the welfare was beyond words. They all said that although the zongzi is small and affectionate, it not only allows everyone to feel the festive atmosphere in advance, but also integrates the company's strong care into the wisps of zongzi. Over the years, Graphite Valley has always attached great importance to the humanistic care for employees. Every traditional festival, it will distribute intimate and affordable welfare items to employees, so that employees can share the development achievements of the enterprise, which not only reflects the "people-oriented" corporate culture of Graphite Valley, but also enhances the cohesion of the team, improves the sense of ownership of employees, and adds impetus to the development of the enterprise.

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Warmly congratulate Comrade "Chen Longqing" on winning the honorary title of "Innovation Expert" in the second session of Harbin New District

Warmly congratulate Comrade "Chen Longqing" on winning the honorary title of "Innovation Expert" in the second session of Harbin New District

Jun 01,2022

On May 31, the first Songbei District (Harbin New District) Model Worker, Model Unit (Collective) and the second New District Craftsmen, New District Innovation Expert Commendation Conference were held in Harbin. The majority of employees in the new district jointly witnessed the first Songbei District (Harbin New District) The highlight moment of the first model worker, model unit (collective), the second new district craftsman, and the new district innovation expert. In order to encourage the majority of employees in the new area to carry forward the spirit of craftsmanship, enhance their sense of innovation, and give full play to the wisdom and strength of industrial workers in the construction and development of the new area, the Songbei District Federation of Trade Unions organized the first selection of model workers and model units (collectives), The District Civil Affairs and Human and Social Resources Security Bureau jointly carried out the second selection and recommend of craftsmen and innovators in the new district. Through grassroots recommend, expert review, comprehensive assessment and publicity, and after discussion and approval by the Standing Committee of the District Committee, 30 model workers, 10 advanced units (collectives), 10 new district craftsmen and 10 innovative experts were commended and rewarded. Comrade Chen Longqing of our company won the honorary title of "the second innovation expert of Harbin New area" by virtue of his outstanding achievements in "process innovation, equipment transformation and technical improvement. As an innovative high-tech industrial group focusing on the fields of new energy and new materials, focusing on the R & D, production and sales of graphite, graphene, carbon materials and their applications, since its establishment, it has been based on scientific development and focused on independent innovation. Adhering to the innovative concept of "science and technology changes the world, innovation leads the future", and constantly pursues technology, product, service and management innovation; in the future, Graphite Valley will build and build a complete ecological block chain of graphite (ene) new material industry through industrial layout, scientific innovation, and combined with the capital market, promote industry development, give full play to Longjiang's advantages, create industrial highlands, grasp development opportunities, and adhere to Innovation leads, determined to become a leader in the new energy and new materials industry, to promote the rapid and healthy development of strategic emerging industries, and to contribute to the sustainable economic and social development.

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Bertrand Grasps Policy Dongfeng to Conquer Key Technologies

Bertrand Grasps Policy Dongfeng to Conquer Key Technologies

Jun 08,2022

In the Beitri High-tech Industrial Park in Guangming District, Shenzhen, production lines in the workshop are running at full capacity. Coinciding with the vigorous development of the new energy industry market, as the world's leading supplier of lithium battery positive and negative material solutions, Bertrand is producing and supplying at full capacity. "This policy comes at the right time for us." Bertrey's policy is "just in time" to be accurate. Just a few days ago, Ren Jianguo, general manager of the company, mentioned in a speech that he hoped to seize the "golden 10 years" of industry development, especially before 2025, to consolidate Beitri's leading position in the anode material industry and bring the company to a new level in all aspects. "Negative electrode material leader" "North Stock Exchange market value of the first brother", with these labels, is a continuous practice of their own "internal strength" of the deep enterprises. On June 6, the "Shenzhen Action Plan for Cultivating and Developing New Materials Industry Clusters (2022-2025)" was released, proposing to combine my country's new generation technology, new energy vehicles and other major needs, focus on industrial development bottlenecks, and overcome a batch of new materials Key core technologies. Ren Jianguo said: "This is the direction Bertrand has been working." Recently, Beitri started the project of "annual output of 40000 tons of high-end anode materials" in Guangming District. As a major advanced manufacturing project, the silicon-based anode materials built by Beitri have broken through the "ceiling" of traditional anode materials and are regarded as the future of anode materials. He Xueqin, Chairman of Bertrand, said: "We attach great importance to the building of overall supply chain capabilities, especially the stable supply mechanism of core key materials." Based on this, the new projects initiated by Beitri all adopt integrated logic, and the self-supply rate of the company's key core processes is expected to reach more than 50%.

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Why is the machine-added graphite plate dominant in the field of graphite bipolar plates?

Why is the machine-added graphite plate dominant in the field of graphite bipolar plates?

Jun 27,2022

According to the research data of the Institute of Hydrogen and Electricity (GGII) of High Industry, Production and Research, the shipment scale of Chinese enterprises hydrogen fuel cell graphite bipolar plate reached 0.294 billion billion yuan in 2021, an increase of 49.24 percent over the previous year. Among them, the shipment scale of machine-added graphite plate was 0.257 billion yuan, up 48.55 over the previous year. In 2021, the proportion of CNC process shipments in the domestic graphite bipolar plate is more than 85%. This is because the machine plus graphite plate itself has advantages, in the graphite bipolar plate cost-effective trend, the production efficiency of the machine plus graphite plate in the increase, the price is down. The fuel cell bipolar plate is the "skeleton" in the stack, which is laminated with the membrane electrode and assembled into the stack, and plays the role of supporting, collecting current and distributing gas in the fuel cell. The importance is self-evident. Currently, fuel cell bipolar plates on the market are classified into graphite (composite) bipolar plates, metal bipolar plates, and the like. Among them, graphite bipolar plate technology has become more mature and occupies a dominant position in market applications. Graphite bipolar plates are divided into machine-added graphite plates (CNC machining process) and molded graphite plates according to different processing techniques. These two technical routes have their own characteristics. The advantage of machine-added graphite plate is that machine-added ink plate itself has the advantages of good conductivity, long service life, high power density, strong stability and excellent product performance. At present, the fuel cell industry is in the demonstration operation stage, and the market purchase volume of bipolar plate is not stable, and most of them are customized products. In this case, downstream enterprises are willing to choose machine-added graphite plate with good processing flexibility and strong adaptability for development and testing. The advantages of the molded graphite plate are short production time and high efficiency, which is more in line with the requirements of commercial mass production of fuel cells. However, compared with the machine-added graphite plate, this technical route is more difficult in process control and quality control, and the initial investment is more. Most fuel cell companies are actively expanding the diversified applications of fuel cells, such as hydrogen forklifts, cogeneration, drones, two-wheelers, etc. The applications in this part of the market are mainly machine-based graphite plates. The rise of diversified development momentum has expanded the market space of machine-added graphite plate. There are not many enterprises in China that can supply molded graphite plate products in batches, and downstream users have more opportunities to select machine-added graphite plates than molded graphite plates. In terms of graphite bipolar plates, it is inevitable that machine-added graphite plates occupy most of the market share.

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Haydale functionalized graphene conductive reinforcing filler

Haydale functionalized graphene conductive reinforcing filler

Jun 29,2022

Every once in a while, there will be new scientific breakthroughs to change the world. According to an information disclosed by the British Haydale Company, a functionalized graphene conductive reinforcing filler developed by Haydale Company is currently a patented technology. The conductive reinforcing filler is added to the functionalized nanoparticles, and finally used in the preparation of prepreg, thereby forming a new type of functional integrated component, the technical director of the Haydale said that the functionalized graphene conductive reinforcement filler of this patented technology greatly enhances the stealth capability of the aircraft, or will bring revolutionary changes in the research process of stealth technology or wave-absorbing materials. Radar stealth is mainly to reduce the radar cross section (RCS) of the aircraft. The main measures are usually: a unique aerodynamic shape design, that is, through a special shape design to control the direction of the radar echo; the use of absorbing materials and absorbing structures that can absorb radar waves, so that the scattering field is weakened, which can not form an effective echo signal. For example, the United States F-117A stealth fighter. In the research process of stealth technology, absorbing materials and absorbing structures have become the biggest contribution point of stealth technology research. Absorbing materials can also be divided into two types from the material composition, one is a coated absorbing material, and the other is a structural absorbing stealth material. The coated wave absorbing material is made by adding wave absorbing agent to resin base or rubber base. This kind of wave-absorbing material construction, can be used brushing or spraying method of construction, can be applied to complex curved surface, such as wave-absorbing paint/stealth paint. However, this coating material has the problem of weather resistance, because it adheres to the surface of the aircraft, the surface adhesion gradually decreases with the change of service life and climate, and even falls off. At the same time, it also faces problems such as follow-up maintenance and repair. Structural wave-absorbing materials are usually made of resin/fiber-reinforced composites as carriers and added with absorbents. It is a kind of multi-functional composite material, which can not only carry the structural parts, but also have the advantages of light weight and high strength of composite materials, and can absorb or pass through electromagnetic waves well. It has become an important development direction of stealth materials. At present, some foreign military aircraft and missiles have adopted structural wave-absorbing materials, such as the horizontal stabilizer of SRAM missile, the edge of the A- 12 fuselage, the leading edge of the wing and the lift aileron, the fairing of the F-111 aircraft, the inlet of the Harrier-Ⅱ aircraft jointly developed by B- 1B, the United States and Britain, and the air-ship bomb ASM-1 and the wing of the ground-ship bomb SSM-1 developed by Mitsubishi Heavy Industries of Japan, in the picture, the UAV is jointly developed by the University of Central Lancashire and Haydale to use nano-graphene wave-absorbing carbon fiber prepreg as the "coat" of the UAV ". The rapid development of composite materials provides a guarantee for the development of structural absorbing materials. The new thermoplastic PEEK, PES, PPS and thermosetting epoxy resin, bismaleimide, polyimide, polyetherimide and isocyanate all have good dielectric properties, and the composite materials made of them have good radar transmission and transmission. In recent years, foreign countries have made a lot of improvement work on carbon fiber, such as changing the cross-sectional shape and size of carbon fiber, surface treatment of carbon fiber surface, so as to improve the electromagnetic properties of carbon fiber, etc., for wave-absorbing structure. The Haydale developed functionalized graphene wave-absorbing stealth filler can be used for the fusion of composite materials and resins without increasing the weight, endowing the body material with radar transmission and transmission, and forming a structural wave-absorbing material. Haydale, after years of research and development, Haydale functionalized graphene conductive reinforcing filler has applied for a patent for a process that allows graphene to be functionalized through a plasma reactor-even if it can be combined with other materials, thereby taking advantage of the properties of graphene and other nanomaterials to give ordinary materials the superpower of graphene.

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