On October 29th, Andre Geim from the University of Manchester in the United Kingdom received a celebrity welcome at the "2015 China International Graphene Innovation Conference" held in Qingdao, China. His name is now as famous as "universal material" graphene. As the Nobel Prize winner in physics in 2010, and the first discoverer of graphene, when he took over an innovative product, Graphene, from a Chinese company, he was slightly serious about his mouth. There is a slight, but meaningful smile. As a new material with a monolayer structure composed of carbon atoms, graphene can be said to be the thinnest and hardest material in the world. It is ultra-thin, ultra-light, ultra-high-strength, super-conductive, and excellent. The room temperature thermal conductivity and light transmission, the structure is also very stable. Not only is it expected to double the efficiency of lithium batteries, it is also expected to replace silicon and create a new generation of supercomputers in the future. Graphene made heatable clothes Found in the laboratory in 2004, by 2010 the discoverer was awarded the Nobel Prize, and now the graphene industry has blossomed all over the world. This kind of new “universal material†representing the next era has unlimited application prospects. However, the current situation of its application is mixed. On the one hand, the graphite mineral resources that are not closely related to the real graphene film are being favored. On the one hand, the concept of purely speculative graphene products has emerged one after another. Compared with the state of the international chain, which is often dominated by technology giants and from research and development to industrialization, China faces the dilemma that graphene research and development is still confined to universities and research institutes and is out of line with actual applications. As far as China's graphene industry goes, it not only needs guidance at the national level, but also needs enough time and enough patience. "Universal material" On October 23, Chinese President Xi Jinping visited Gem's National Graphene Institute at the University of Manchester. In the morning, Huawei, a Chinese company, announced that it is cooperating with the University of Manchester to jointly develop the next-generation high-performance technology in the ICT field and study how to apply breakthrough achievements in the graphene field to consumer electronics and mobile communication devices. Ren Zhengfei, the founder of Huawei, has talked about graphene several times before and proposed that “the greatest subversion in this era will be the graphene era that will overturn the silicon era†and believes that there will be a technological revolution in the next 10 to 20 years. Graphene is a two-dimensional honeycomb crystal lattice consisting of a single layer of carbon atoms. Its theoretical thickness is only 0.34 nanometers. It has excellent thermal conductivity, mechanical properties, high electron mobility, high specific surface area and quantum Hall effect and other properties. It is because of these special and excellent physicochemical properties that graphene shows potential applications in microelectronics, physics, energy materials, chemistry, biomedicine and other fields. In 2004, Andre Gaim and Konstantin Novoselov of the University of Manchester in the UK stripped graphene from graphite flakes, and both of them won the 2010 Nobel Prize in physics. Although the method they used was very original, the greatness of this discovery lies in breaking the conclusion of the international physics community for up to half a century that stable graphene could not be obtained. In fact, in the same issue of Nature that published Gay's famous paper, an article by Chinese scholar Zhang Yuanbo and collaborators on graphene was also published, but the Nobel Prize did not favor the latter. At that time, it was considered as the most recent domestic scholar from Nobel. Zhang Yuanbo’s work with collaborators and Gaim’s team in 2005 led the world’s research on graphene. Since then, Zhang Yuanbo's work has mainly focused on the preparation of graphene, electrical transport properties, scanning tunnel energy spectrum, and far-infrared energy spectrum measurements, and has been active in the forefront of this field. Zhang Yuanbo told the Caixin reporter that after discovering the new physical phenomenon of graphene by the two teams, this area has seen explosive growth, and there is no sign of saturation. The most critical part of the smartphone that the public will use every day is a touch screen that is both conductive and very transparent. Graphene happens to have such a characteristic that it can be made into such a touch screen. Graphene also has better strength and flexibility than the current transparent electrode material, indium tin oxide (ITO). As early as 2010, researchers from Sungkyunkwan University and Samsung Electronics Co., Ltd. produced a transparent and flexible display composed of multilayer graphene and polyester film substrates. At the time, Hong Bingxi, the author of the paper's correspondent and professor at Sungkyunkwan University, proposed that their methods could be used to make graphene-based solar cells, touch sensors, and flat panel displays. However, he also admitted that large-scale manufacturing and commercialization are still too early. However, the development in the past five years also exceeded his expectations. At the Graphene Innovation Conference held in Qingdao at the end of October, Hong Bingxi introduced that graphene transparent electrodes have been widely used in a variety of flexible optoelectronic devices, including touch screen sensors, organic light emitting diodes (OLEDs), and organic photovoltaic devices. Due to its excellent thermal conductivity and mechanical properties, graphene also shows many potential applications in sensors, polymer nanocomposites, optoelectronic functional materials, and drug controlled release. Graphene has a large specific surface area, which makes it possible to fabricate high-sensitivity sensors. Once the gas is adsorbed on the surface of graphene, the surface resistance of the graphene will change, and then combined with an electrical sensing detector, graphene can be made available. Become an excellent gas sensor. Graphene's gas adsorption properties also make it a new type of hydrogen storage material that can quickly and reversibly absorb and release hydrogen at room temperature and under safe pressure with high thermal stability. Graphene's unique two-dimensional layered structure and good biocompatibility make it a good drug carrier. Scientists reacted graphene with antitumor drugs to produce complexes that can slowly release drugs in the human body, and the load of the drug is much higher than that of traditional drug carriers. According to Cheng Huiming, a researcher at the Institute of Metals of the Chinese Academy of Sciences, graphene has broad application prospects in the field of clean energy. The biggest problems with clean energy are stability and mobile storage challenges. The storage methods are mainly supercapacitors and batteries, all of which need to meet high energy density, high power density, high reliability, and long life. Graphene can increase the conductivity of lithium battery electrodes. They apply the graphene mixture to lithium batteries and their cruising range can be increased to more than 400 kilometers. On the other hand, it is used for flexible energy storage. In the future, it will be used for flexible wearable devices and flexible smart devices. "To be flexible, flexible energy sources are also required, including flexible lithium batteries and flexible supercapacitors." In an interview with a reporter from the "Science and Technology Daily", Gaim expressed with emotion that he and his colleagues discovered the global R&D and commercialization of graphene in just a few years after he and his colleagues discovered that the graphene was awarded the Nobel Prize in physics in 2010. He was very surprised. Preparation problems People are familiar with the interesting fact that André Gaim obtained graphene with transparent tape, and thus won the Nobel Prize. In fact, after obtaining graphene with transparent tape, they began to develop mechanized graphene production methods. In 2004, they succeeded in preparing monolayer graphene by micro mechanical peeling. This method is of course more primitive. Although graphene with a relatively complete crystal structure can be obtained, the resulting graphene has a small size, generally between 10 micrometers and 100 micrometers, and has the disadvantages of low yield and high cost, and can not meet the requirements of industrialization and large-scale production. Since then, people have thought that it is not necessary to use graphite for the preparation of graphene, but it is only necessary to try to make the carbon atoms form a thin film. Chemical vapor deposition (CVD) came into being. This method introduced ethylene or acetylene gas into a reaction chamber. These gases were decomposed at high temperatures. After cooling, carbon atoms were deposited on the substrate surface to form graphene. Finally, the metal substrate is removed by chemical etching or transferred to a polymer film by a roll-to-roll method. Although CVD can meet the requirement of large-scale, high-quality preparation of graphene, its application in graphene preparation is limited due to its high cost and complicated process. Peng Hailin, professor of Peking University's Center for Nanochemistry, told Caixin reporters that they could use melamine to pre-treat the copper foil and reduce the condensation point on the copper foil, so that large graphene films could be formed to improve the light transmission of the film. Conductivity and consistency, and then through the roll-to-roll method, the graphene film is transferred to the high-molecular PET film, you can get high-quality graphene film. In the roll-to-roll transfer process, the metal nanowires are encapsulated between the graphene and the flexible plastic substrate to form a composite conductive film, which can exhibit excellent conductivity, light transmission, and excellent flexibility and mechanical stability. Sex, peel resistance and chemical resistance. They used graphene and silver nanowire composite electrodes to prepare electrochromic devices, which have good discoloration properties, rapid color change corresponding time and stable cycle performance. This kind of composite electrode has great potential application value in the field of next-generation flexible electronics and optoelectronics. Graphene oxide reduction is one of the most commonly used methods for preparing graphene in the area where the film area of ​​graphene is not excessively high. This method was proposed as early as the middle of the last century and has been used until now. Under the action of strong oxidants, the graphite layer spacing was expanded to form a uniform monolayer of graphene oxide after sonication in an aqueous solution or organic solvent, and then graphene was prepared by reducing the oxidized group with a reducing agent. But this method is mainly graphene powder. There are many defects, poor electrical and mechanical properties, and the need to oxidize graphite with concentrated sulfuric acid. The disposal of industrial waste liquids is a problem. There is also a main method - solvent stripping method, the principle is to disperse a small amount of graphite in the solvent to form a low concentration of the dispersion, the use of ultrasound to destroy the molecular interaction between the graphite layers, this time the solvent can be inserted between graphite layers The layers were peeled to prepare graphene. This method does not destroy the structure of graphene like the oxidation-reduction method, and high-quality graphene can be prepared. Since the entire liquid phase peeling process does not introduce any defects on the surface of the graphene, it provides a wide application prospect for its application in the fields of microelectronics, multifunctional composite materials, etc. The disadvantage is that the yield is very low. It can be seen that different graphene production techniques are crucial for graphene manufacturers because it not only affects the size of the graphene, but also affects the quality and cost as well as the application field. Graphene nanosheets can be applied to energy storage devices such as printed electronics, conductive inks, lithium ion batteries, and super capacitors. Graphene prepared by CVD has the advantages of scalability, high conductivity, and large-scale production. It can be successfully applied to high-end electronic applications. Due to the huge differences in the preparation methods, the price between the graphene powder and the CVD film is also a thousand times different. For example, 1 gram of graphene powder only requires less than 10 yuan, and 1 square metre of graphene film is tens to hundreds of yuan, and its weight is actually less than 1 milligram. In the eyes of industry experts, the main challenge of graphene is to meet two conditions at the same time: low cost and high quality. Shi Yi, a senior analyst at Haitong Securities, pointed out that the liquid phase redox process is currently the main production method for mass production. The price of graphene can be reduced to 10 yuan/g or less. The finished products are mostly powder materials and slurry materials, and can be formed indirectly. For low-end applications. The CVD method can produce graphene films directly, which is of higher quality and better performance, but the price is very expensive. In the future, if the technology advances and the demand amplifies the scale effect, the cost is expected to decrease rapidly. Mixed applications As a "universal material," people naturally want to apply graphene to all applicable fields. In this vigorous upsurge, the imagination of many domestic companies has also been greatly released. At the Graphene Innovation Conference held on October 28-30, in addition to the sub-forums that narrate the industry applications, a very important part is the display of manufacturers. The one that attracted the most attention was a booth from a company in Jinan. Unlike other materials displayed in other booths, there are a large number of on-site sale of underwear, underwear and socks. The colors of these clothes are all dark gray or black. From the point of view of the clothes, there is no difference from ordinary clothes. The booth staff introduced the use of graphene as raw materials. They carbonized plant stalks to extract graphene, using the superconductivity of graphene as a raw material for the production of clothes. After the use of graphene, sweat absorption is enhanced and there is no need to worry about static electricity. Graphene socks can prevent foot odor. This kind of application is an eye-opener to a Danish expert who travels with Caixin reporters. What he did not know was that when the concept of nanomaterials first emerged many years ago, nanopanties were immediately available in China, as well as nano ties, nano washing machines, and nano refrigerators. Therefore, when André Gaim, the Nobel Prize winner in physics, held a special gift from a Chinese company, “Graphene smart waistband,†his smile seemed meaningful. According to the "2015 Global Graphene Industry Research Report" published by the China Graphene Industry Technology Innovation Strategic Alliance on October 30th, China not only ranked number one in the number of published graphene papers at the end of 2012, but also in the past three years. Fast forward, but the innovation of the quality of the paper needs to be improved. When Gaim was interviewed by Chinese media, he pointed out that of the many published graphene papers, half of the research will be abandoned. On the other hand, many patents, especially patents from universities, 90% of which are worthless, 99% of patents will eventually be invalidated, and the maintenance of these patents will also cost a lot of money. Many people are wasting lives for this. Kang Feiyu, dean of the Shenzhen Graduate School of Tsinghua University and a carbon materials expert, had publicly stated that although China ranks first in the world in the publication of graphene papers, many scientific research institutes do not know exactly what the industry wants and the disconnect between research and application. prominent. Peng Peng, vice president of Changzhou 2D Carbon Technology Co., Ltd., told Caixin reporters that they were established in Changzhou in 2011 and have now grown to a scale of 200 people. In 2012, they produced the world’s first capacitive graphene touch screen. The current production capacity has been It reached 150,000 square meters. However, in the last two years, the mobile phone market was not good. They also used the high heat radiation efficiency of graphene films to develop some heatable clothes. Their research and development direction also includes graphene composites, solar cells, and wearable sensors. Tsinghua University's Micro-Nano Mechanics Center Professor Zhu Hongwei told Caixin that there are some graphene applications in China that are actually speculative. There are actually only a few companies that actually do graphene. Many of them are carbon materials such as graphite. There are only a handful of firms that are completely unrelated to the name of graphene, or speculating on stocks, or striving for state funds. They are truly graphene and truly profitable companies. In his opinion, it is impossible to completely negate the application of graphene underwear and graphene waist protection. This may be a good way for the public to accept the new phenomenon of graphene, and it will be effective if it can find more. The specific health care application market will have even greater development. Of course, the development of graphene industry also needs to find the real application of graphene, that is, the "monopolized" application that can reflect the advantages of graphene. According to Zhu Hongwei, the current application of some graphenes can be accomplished with the original carbon materials, and the advantages are not obvious. Non-graphene is not a truly valuable application and it is still in the laboratory at this stage. Dr. Zhong Cheng, CEO of Qingdao Huagao Methylene Technology Co., Ltd., told Caixin reporter that the heating function of graphene should not be underestimated. "You can heat up with very little current and very low power. Only graphene and carbon nanotubes can do it, so you can drive it with a cell phone battery." Therefore, military, life-saving heating clothes are a product they are developing. Other products include ballistic materials and coatings using graphene composites, portable water treatment equipment utilizing graphene films, and modification of energy storage cells. He also admitted that these applications, in fact, no graphene looks so "tall"; they use the material is not expensive CVD graphene film, but modified film made of graphene powder, the cost is Much lower. He said that graphene is nothing more than a carbon material, and there is no essential difference between carbon fiber and nanotubes. The key is to see where it is used. As long as the cost-effectiveness is good enough, the market is large enough and it is a good application. In his opinion, whether “tall†is not a criterion for judging whether the graphene industry is a mixed bag. He believes that the phenomenon of purely speculating the concept of graphene has two types, one is to use graphene concept to pull up stocks, and the other is to use graphene concept, not to really do graphene, to blow up data very ridiculous, such as Some companies claimed that charging eight kilometers to run 1000 kilometers, which is scientifically speaking, is very unreliable. "The industry is also very helpless." He said that related companies very much hope that everyone's attention, but excessive speculation is a kind of injury. The company that does graphene really does not have more than 40 companies in the country. The real money makers are even fewer, and others are still burning money. Need patience In 2015, for the entire graphene industry, it has been able to describe it vigorously. In many people's eyes, 2015 can be seen as the first year of commercialization of graphene. However, behind the noise, the fact that can not but ignore the existing commercial applications is still a limited improvement on the existing materials, and there is no qualitative improvement, and people are looking forward to replacing silicon with graphene, manufacturing "super The dream of computer is still far away. Shi Yi pointed out that the application of graphene in short-term rapid industrialization includes lithium ion battery conductive additives, functional coatings, touch screens, etc.; electrode materials for electronic devices such as super capacitors, which are expected to be industrialized in the mid-term, etc.; long-term, graphene can Breaking ice in the industrialization of terahertz detection, various types of sensors, and laser applications will bring breakthroughs in many fields such as medicine and military industry. In his opinion, the characteristics of adsorbing charge, adsorbing impurities, etc., are not the focus of graphene applications. As a new material, applications must have quantity, so flexible displays will be a key area. From an application perspective, graphene is still in the stage of storytelling. The degree of development can only be said to be in line with expectations, and in China, the progress of production, education and research is even lower than expected. Obstructing large-scale applications is of course a technical problem. Only in the field of touch screens and flexible displays, the difficulties are not small. Prof. Hong Bingxi from Korea pointed out that the integration of graphene transparent electrodes into commercial equipment must also overcome considerable challenges. Among them, the development of consistent and repeatable synthesis methods for low-cost, large-scale, high-quality graphene is the greatest difficulty. Especially when using graphene electrodes, the equipment architecture needs to be customized into a two-dimensional structure, which is why graphene cannot replace ITO immediately. Therefore, Hong Bingxi predicts that the application of graphene in flat and simple structures will be realized first, such as touch screens, smart windows, electromagnetic interference shields, lighting, and transparent heaters. However, in flexible displays and microelectronic devices, Take some time. According to industry experts, the current industrial standards for the size, uniformity, and reliability of graphene in consumer electronics have not yet been determined, and thus the actual use of graphene in consumer electronics has not yet been demonstrated. Zhu Hongwei told Caixin that the advantage of using graphene on rigid touch screens is not obvious, and the yield, reliability, and service life all face many challenges. Unless transparent conductive, integrate other functions. In addition, it is a real advantage in flexible devices, and it is difficult for other materials to remain stable during bending. He believes that the problem to be solved by graphene is still to seek a breakthrough in the preparation technology of the material. The quality of the graphene film itself cannot meet the requirements of high-end electronic applications. On an integrated circuit, you can make small-scale devices in the lab. Mass production and integration quality cannot be guaranteed. "At least I can't see hope at the moment." He revealed that Gaim himself has reservations about the current commercialization of graphene. He believes that graphene is an introduction and has led to the development of a wider range of two-dimensional materials. At present, for the graphene, from the physics point of view, it has reached a bottleneck. In the future unless there is a greater breakthrough, it is difficult to further improve. Behind the turbulent commercialization, the fundamental research on graphene in the country is out of touch with the industry. Liu Ronghua, deputy secretary-general of the Graphite Professional Committee of the China Non-metallic Minerals Industry Association, said that foreign companies are mainly dominated by large companies, such as Samsung, Sony, and IBM, while research institutes and universities in China are often out of touch with applications. Zhu Hongwei told the Caixin reporter that Huawei’s investment in the UK rather than the country also saw the difference in the country. "We should gradually guide financial capital into this industry," and for this reason they are studying the establishment of a graphene industry merger and acquisition fund. At the opening ceremony of the Graphene Innovation Conference on October 29, Wang Jianhua, Chairman of the China-Industry Cooperation and Research Promotion Association, said that while the industry is vigorous and vigorous, everyone must keep a clear head and not be able to embrace them. According to Dr. Zhong Cheng, CEO of Huagao Methylene, from a good perspective, China's industrialization is ahead of the world. The bad news is that basic research has not kept pace, and foreign countries pay more attention to basic research and are not in a hurry to commercialize. Focusing on the research and development of graphene integrated circuits, the study of graphene based on its physical properties will, in the long run, be a true “tall†application. “We feel as if we are weak in succession. In another three to five years, the momentum of development will slow down and the advantages of Europe will be reflected. The more ideal result is that their achievements have been applied to us.†He believes that China's problems in basic research are mainly due to the lack of national guidance. The EU's "Graphite Flagship Program" has a good division of labor, basic research, applied research, policy research, and even research. How to educate, how to manage, this kind of macro design is more mature, and the enterprise can't do this input. “Because the concept of graphene has been sought after by the capital market and the industrialization has developed rapidly, we have forgotten what to do slowly and patiently. It can not be said that the level of colleges and universities is poor, but the lack of national guidance.†He said. Most of them are hype. Of course, there are still many well-informed people who can see the law of development in this area. Zhou Changyi, director of the Ministry of Industry and Information Industry's raw materials industry, revealed on October 29th that the National Thirteenth Five-Year Plan for the development of new material industries, including the graphene industry, is being prepared and will be introduced soon. He said that the Ministry of Industry and Information Technology is currently working with relevant departments to formulate certain opinions on accelerating the innovation and development of the graphene industry, guiding the establishment of a graphene industry development alliance, actively establishing a joint innovation center for graphene industry, and increasing services for the development of the industry. Zhong Cheng believes that when formulating graphene-related planning, China cannot simply integrate materials submitted by various localities, but must have a long-term vision, ability to lay out, grasp the ability of time, and complete many things that are not profitable as preparations. .
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