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Graphite Valley was invited to participate in the new material industry promotion meeting of the 40th anniversary of Dalian Economic and Technological Development Zone

Graphite Valley was invited to participate in the new material industry promotion meeting of the 40th anniversary of Dalian Economic and Technological Development Zone

Sep 27,2024

In 2024, Dalian Economic and Technological Development Zone, known as "China's first Development Zone", ushered in the 40th anniversary of its establishment. Over the past 40 years, Dalian Economic and technological Development Zone has gone through an extraordinary road of struggle, vividly interpreting the strong vitality of reform and opening up. Graphite Valley Industry Group, as an outstanding enterprise in Dalian Economic and Technological Development Zone, was invited to participate in the conference. Graphite Valley Industry Group Chairman Fang Zhenhui, Executive Vice President Mei Jia was invited to attend the meeting.

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The Shenzhen delegation came to Harbin to further promote the cooperation between Shenzhen and Harbin.

The Shenzhen delegation came to Harbin to further promote the cooperation between Shenzhen and Harbin.

Jul 09,2021

On May 8, 2019, Wang Weizhong, deputy secretary of the Guangdong Provincial CPC Committee and secretary of the Shenzhen Municipal CPC Committee, led a Shenzhen delegation to Harbin for a two-day inspection to further promote counterpart cooperation between Shenzhen and Harbin. Wang Zhaoli, member of the Standing Committee of the Heilongjiang Provincial Party Committee and Secretary of the Municipal Party Committee, and other leaders of Harbin City accompanied the inspection. The delegation used one day to visit industrial parks, high-tech enterprises and universities in Harbin. Learn more about Shenzhen Harbin industrial project cooperation, product research and development, scientific and technological innovation and achievement transformation, personnel training, etc. The delegation visited Wanxin Graphite Valley Graphite (ene) New Material Industrial Park Source: Harbin News Network-Harbin Daily

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Wang Wentao: Combining Production, Learning and Research to Promote the Development of Graphite Industry

Wang Wentao: Combining Production, Learning and Research to Promote the Development of Graphite Industry

Jul 09,2021

Northeast Network, September 12 (Heilongjiang Daily reporter Wang Kun) On the 12th, Wang Wentao, deputy secretary of the provincial party committee and governor, went deep into Harbin Wanxin Graphite Valley and Harbin Institute of Technology to investigate the development of the graphite industry. He emphasized that it is necessary to thoroughly implement the spirit of General Secretary Jinping's important speech to our province, adhere to the development of resource development and intensive processing, and the industrialization of high-tech achievements, with the help of Longjiang's rich graphite resources, scientific and technological innovation foundation, and talent advantages., Through the combination of production, education, research and application, extend the graphite industry chain to accelerate the industrialization of graphite, and do a good job in the "new name" article. In Harbin Wanxin Graphite Valley Technology Co., Ltd., Wang Wentao has a detailed understanding of the outstanding problems faced by enterprise technology research and development, market prospects and development. Photo by Sun Qiang In Harbin Wanxin Graphite Valley Technology Co., Ltd., Wang Wentao has a detailed understanding of the outstanding problems faced by enterprise technology research and development, market prospects and development. Wang Wentao said that graphite has become an important new material for the development of emerging industries. With the breakthrough of research and development of new graphene materials and industrial application, it has brought important opportunities to our province. We should give full play to the advantages of China's graphite industry alliance, plan the industrial development direction and technology application fields according to the overall planning and deployment of the country's graphite industry, Transform resource advantages into industrial advantages, and improve the deep processing level of graphite resources, drive the development of related industries and build the graphite industry into a large-scale and competitive emerging industry. In Harbin Institute of Technology, Wang Wentao has a detailed understanding of the development and application of graphene technology. Photo by Sun Qiang In Harbin Institute of Technology, Wang Wentao has a detailed understanding of the development and application of graphene technology. He emphasized that it is necessary to rely on the technological advantages of universities and scientific research institutes, and through the construction of a technological innovation system with enterprises as the main body, market-oriented, and a combination of production, education, research and application, to promote the transformation of the graphite industry from scientific research to achievements to the extension of the upstream and downstream industrial chain. Agglomeration, and then drive technological leaps through the wide application of new graphite materials. He said that governments at all levels should actively create a good environment for innovation-driven development, attach great importance to the technology spillover of scientific research projects, and promote the application of military-civilian integration technology to more civilian fields. Vigorously promote the docking of capital markets and technological innovation. Through technical consultation, transfer, equity cooperation and other aspects, encourage and stimulate the vast number of scientific and technological personnel to transform scientific and technological achievements into products, improve the entrepreneurial enthusiasm of executives, and retain and make good use of high-tech talents. Source: Northeast Network

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Industry dynamics... Speaking of "lithium" all over the world.

Industry dynamics... Speaking of "lithium" all over the world.

Mar 07,2022

Industry data show that from 2020 to 2025, the compound growth rate of electric vehicle sales is 48% (about 23 million electric vehicles sold in 2025, with a penetration rate of about 27%). Such a violent growth in electric vehicles, corresponding to lithium battery raw material lithium demand, is expected to maintain a compound growth rate of 37%. The rapid growth in demand for lithium resources is due to the fact that in the lithium battery technology route, whether it is lithium iron phosphate, lithium cobalt oxide, or ternary materials, lithium is a necessity, and the material accounts for a relatively stable proportion. Among them, ternary materials (commonly used are NCA and NCM) have advantages in energy density, volume capacity and cycle performance. The lithium iron phosphate material mainly uses lithium carbonate, which has the advantages of relatively low cost and strong safety. It is used in the fields of entry-level models, electric buses and energy storage. In addition, lithium batteries continue to grow in the downstream demand for lithium. In 2010, lithium batteries accounted for 27% of lithium downstream demand, and traditional industries such as grease and ceramics accounted for 73%. By 2020, traditional industries have dropped to 31%, and the total demand for lithium in power, consumption and energy storage batteries has reached 69%, which is expected to reach more than 90% in 2025. Talk about "lithium" demand growth Market conditions show that the global lithium industry demand in 2020 is about 300000 tons of LCE, and the lithium industry demand is expected to exceed 1.4 million tons by 2025, with a compound growth rate of 37%. In terms of supply, although the global lithium supply has grown steadily, it is far from keeping up with market demand. Price, due to the terminal new energy development greatly exceeded expectations, bringing midstream battery materials have been expanded. This directly allowed the price of lithium to explode, first from 40000 yuan/ton to 90000 yuan/ton, and then broke through 180000 yuan/ton, and then rose again after a short-term shock. As of December 31, 2021, the Asian metal network battery grade lithium carbonate quotation has reached 278000 yuan/ton, significantly exceeding the highest point of lithium price in 2018. By the first quarter of 2022, the price has soared to more than 400000 yuan/ton, and there is also a selling price of 500000/ton in the market. It can be seen from the price that for the entire lithium battery industry, the stable and high-quality supply of upstream materials has become the key to continued rapid development. Lithium supply bottleneck in salt lake lithium extraction At present, the existing forms of lithium resources that can be economically exploited mainly include salt lake brine, spodumene, lithium mica and lithium clay. The global lithium resource deposits are mainly divided into solid lithium ore and salt lake brine lithium ore, of which solid lithium ore is divided into pegmatite type and sedimentary rock type, such as spodumene, lithium mica ore mainly belongs to pegmatite type. According to USGS2012 -2010 data, about 58% of global lithium resources exist in the form of closed basin brine, and lithium resources in the form of pegmatite account for about 26%. Salt lakes account for the largest proportion of many forms of lithium resources. Different resource types correspond to different lithium extraction processes and lithium salt products. According to different types of resources, the lithium extraction process can be roughly divided into salt lake lithium extraction and ore lithium extraction. Lithium extraction from ore: take the relatively mature sulfuric acid roasting process as an example, the main process flow includes: ore sorting-high temperature roasting-sulfation roasting-dissolution-impurity removal-lithium precipitation, the process is relatively simple, the lithium recovery rate is high, but the energy consumption is large, the required auxiliary materials are more, so the production cost is higher. Salt lake lithium extraction: Compared with ore lithium extraction, salt lake lithium extraction energy consumption, the required auxiliary materials are relatively small, so the corresponding production costs are lower, the cost is mainly concentrated in the salt field construction and other early investment. Due to the poor versatility of the salt lake lithium extraction process, the expansion rate of salt lake production is relatively slow, and the expansion pace of global salt lake production enterprises is relatively limited. If there is a big breakthrough in salt lake lithium technology and the speed of expansion, the shortage of lithium resources will be alleviated in the future. Lithium supply bottleneck in salt lake lithium extraction In 2014-2020, with the increase in lithium demand, global lithium supply increased from 59000 tons of LCE to 439000 tons, a compound growth rate of 40%, of which Australia and South America are the main supply, both accounting for about 80% of the total. By 2020-2021, Australia's lithium pyroxene mine is still the main supply, while South America's salt lake resources have not yet been released in large quantities and have not kept pace with supply. However, with the release of production capacity such as salt lakes in South America, Australia's share of lithium flint supply will decrease. At the same time, the supply of salt lakes and lithium mines in China will gradually catch up and the share will increase. In 2021, China's total lithium salt production reached 410000 tons of LCE, Western Australia lithium concentrate, South American salt lake resources mainly flow to China, and from China's output of lithium hydroxide (mainly from lithium concentrate smelting) a large number of exports to Japan and South Korea and other demand countries. China is becoming the largest demand and production area for lithium salt. As the capacity expansion rate of the smelting side is less than 1 year, the capital expenditure cycle of the lithium mine is about 3 years, and the capital expenditure cycle of the salt lake is about 5 years. Today's lithium industry shortage, it is the resource end of the expansion rate is much lower than the smelting end. For the problem of lithium shortage, how to ensure the supply of lithium without being subject to market fluctuations has increasingly become the focus of raw material companies.

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Current Situation of Spherical Graphite Industry

Current Situation of Spherical Graphite Industry

Apr 27,2022

Spherical graphite is a high-quality high-carbon natural flake graphite as raw material, the use of advanced processing technology to modify the surface of graphite, the production of different fineness, shaped like an elliptical spherical graphite products. The standard of "Spheroidized Natural Graphite" (JC/T 2315-2016) is applicable to spherical or spherical graphite products made from natural flake graphite and processed by mechanical and physical methods, and points out that the physical and chemical properties of spheroidized natural graphite should meet the following requirements Spherical graphite has the advantages of good conductivity, high crystallinity, low cost, low charge and discharge potential and flat, long cycle life, green environmental protection and other characteristics, has gradually become the replacement of lithium-ion battery production of anode materials. At present, China has successfully applied the development of natural flake graphite raw materials to adapt to the production of lithium-ion batteries, that is, the modified products of spherical graphite, so the lithium-ion battery industry chain has entered a new era. According to the data, in 2020, China's lithium battery anode material market size increased to 14.02 billion yuan, 2016-2020 annual compound growth rate of 21.4, is expected to reach 15.91 billion yuan in 2021, shipments increased to 36.5 tons in 2020, is expected to reach 40.1 tons in 2021. At the same time, in the past five years, the domestic spherical graphite industry market average price overall downward trend, by 2020 the average price fell to 17800 yuan/ton, which will greatly reduce the production cost of lithium-ion battery anode materials to a certain extent. In summary, with the continuous expansion of lithium-ion battery anode material shipments and market scale, it will continue to drive the demand and sales growth of spherical graphite. According to the data, in 2020, China's spherical graphite industry sales of 112000 tons, is expected to reach 124000 tons in 2021; sales revenue of 1.949 billion yuan, 2016-2020 compound annual growth rate of 16.8, and is expected to reach 2.207 billion yuan in 2021. In addition, the United States, the United Kingdom, the European Union and other countries or regions have gradually realized the key role of graphite in energy transformation and environmental protection, and issued a series of policies to gradually make graphite a strategic resource. However, the Ministry of Industry and Information Technology of China also issued the "Standard Conditions for Graphite Industry" in 2020, which clearly no longer pursues quantity and deleted the scale indicators such as "the design scale of new and expanded flake graphite beneficiation projects shall not be less than 20000 tons/year", which will be implemented from June 24, 2020, while the "Access Conditions for Graphite Industry" issued in 2012 will be abolished at the same time. By comparing the two documents, it can be found that the protection of graphite in the new edition of the conditions is obviously upgraded, which is suitable for the strategic protection of resource status. Therefore, the promotion of the strategic position of graphite resources at home and abroad will provide a better policy and social foundation for the spherical graphite industry and promote the rapid development of the industry.

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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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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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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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