New Material: Industrialization Of Ramie Carbon Supercapacitor

Ramie is a natural textile material. In Yang Weiqing's eyes, it can also prepare activated carbon electrodes and be used in supercapacitors.

Yang Weiqing is a professor in the School of Materials Science and Engineering of Southwest Jiaotong University (hereinafter referred to as Southwest Jiaotong University), and has been engaged in the research of advanced energy storage materials and devices for a long time. Since 2015, he has focused on this "never rotten soft gold" and started the research on the industrialization of supercapacitors based on ramie charcoal.

He stressed that we must seek truth from facts and let professional people do professional things.

From Coconut Shell to Ramie Stalk

Compared with traditional capacitors, supercapacitors usually have higher energy density and power density, fast charging and discharging speed, and long cycle life, so they are widely used in many fields such as subway kinetic energy recovery, new energy urban transportation, aerospace, and so on.

"The key to determining the energy density of supercapacitors is the electrode material." Yang Weiqing made an analogy, "just like a house, it determines how many people can be loaded." Activated carbon has become the preferred electrode material for supercapacitors because of its advantages such as large specific surface area, adjustable pore structure, good chemical stability and low cost, which is used to absorb charges to store energy.

Coconut shell, as a raw material, is widely used to prepare capacitor activated carbon. However, this technology and large-scale production line have been firmly held by foreign enterprises, which is a major "choke" problem in the development of China's supercapacitors.

"Shu hemp and Wu salt have been popular since ancient times, and the boat of ten thousand dendrobium trees is like the wind." Since ancient times, the ramie produced in Sichuan has been well-known and circulated in many places, including the ramie produced in Dazhu County. For Yang Weiqing, who grew up in Dazhu, the ramie, which grows three seasons a year and can grow up to 2 meters high, is a familiar specialty of his hometown.

"Ramie and coconut shell are both biomass, can ramie also be used for the preparation of electrode materials?" In 2015, when the idea "popped" in Yang Weiqing's mind, he began to research.

Ramie straw has the characteristics of low ash content and high carbon content, and is an ideal raw material for preparing activated carbon with high specific surface area. "Moreover, ramie has high cellulose content, orderly fiber orientation, and loose and porous characteristics. Compared with the activated carbon prepared from coconut shell, the activated carbon prepared from ramie can better store energy," said Luo Qitian, a member of Yang Weiqing's team.

"My hometown is full of ramie, especially the ramie stalks, which are not wanted by anyone, and can also pollute the environment when burned." Yang Weiqing received the waste ramie stalks from fellow villagers, and turned them into advanced materials with high added value.

The process of trial and error

In the laboratory of Yang Weiqing's research group, a high temperature tube furnace witnessed the starting point of ramie carbon preparation research.

According to a series of experimental requirements, Yang Weiqing and his team have explored a set of preparation methods including more than 30 processes in their continuous attempts. After peeling or culm crushing, ramie not only needs carbonization and activation treatment, but also goes through purification processes such as iron removal, pickling, rinsing and filtration. The most critical carbonization process is mainly completed in the high-temperature tubular furnace. "In argon atmosphere, set certain parameters to braise ramie."

In the experimental stage, Yang Weiqing successfully developed the desired active material, but the output was only 100g. There is still a long way to go to realize large-scale production of materials, apply them to energy storage devices to make capacitor products, and finally enter the sales and circulation link. Among them, the most important is the pilot test.

In the college, Yang Weiqing has gradually built an extra capacity carbon pilot line with an annual output of 5kg. "This is a process of trial and error, not just technical improvement."

Because it is to prepare new materials and there is no standardized production equipment on the market, Yang Weiqing has to modify similar devices by himself. "Like the boiler activated by high temperature steam, because the flow and temperature cannot meet the process requirements, four boilers have been replaced." The current boiler also has Yang Weiqing's "transformation" trace: the connecting pipes are wrapped with heating belts one after another to avoid heat loss.

After the production of kg ramie charcoal was realized, Yang Weiqing aimed at "tons" of target output. At the beginning, he was a bit "ambitious" and directly planned a production line with an annual output of 300 tons, but the capital risk and experimental risk were too high and he had to give up finally.

"In actual operation, I found that the risk of doing so was extremely high. The investment in equipment alone would cost 50 million yuan a year. If it was not suitable to refit, it would cost too much money." Yang Weiqing narrowed his goal to a pilot line with an annual output of 30 to 60 tons, and while respecting the law of scientific research, he reasonably planned the time and funds to be invested.

Shortly after the start of ramie charcoal research, Southwest Jiaotong University carried out a "mixed ownership reform of title scientific and technological achievements", and successively issued the Patent Management Regulations of Southwest Jiaotong University and the Intangible Assets Management Measures of Southwest Jiaotong University. The former enables scientific researchers to share the ownership of achievements with their units from the very beginning, while the latter stipulates that the scientific and technological achievements of university posts are no longer included in the management list of state-owned intangible assets, but are managed by the scientific research management department of the university as achievements, thus breaking the situation that university achievements are "unwilling to transfer" and "dare not transfer".

Taking advantage of the policy, Yang Weiqing also met a satisfactory partner after he set the goal of a 30 ton annual pilot production line.

In January 2021, Yang Weiqing's team made 9 service inventions involved in the "key materials and device preparation process series technology of high specific energy supercapacitor". After the division and confirmation of intellectual property rights were completed at a ratio of 3:7 between the school and the scientific research team, they became shareholders of a science and technology enterprise in Sichuan at a valuation of 13.88 million yuan. Among them, 30% of the school's intellectual property rights were purchased by the company with a contribution of 4165740 yuan.

The whole transformation process is not complicated, so it is not necessary to report to the State owned Assets Management Office, the President's Office and the Standing Committee of the Party Committee for approval, but only to publish it on the website of the Research Institute of Science and Technology Development of Southwest Jiaotong University.

Professional people do professional things

Yang Weiqing and his team completed the preparation of kilogram ramie charcoal in the school, and then sent it to the cooperative company's factory in Longquanyi District, Chengdu to make commercial soft bags and cylindrical supercapacitors, and conduct performance test and analysis. This semi-automatic pilot production line for seal testing has been running for nearly two years. Various processes in the process have been mature, and now it is in the running in stage of various equipment.

Yang Weiqing has already planned to build a pilot production line with an annual output of 30 to 60 tons for ramie carbon preparation for a space of more than 2000 square meters reserved in the plant area.

"The enterprise I worked with used to be mainly engaged in printing business." Yang Weiqing said that after the second generation of helmsman took over, he wanted to transform the company, but he was just looking for investment, so they hit it off.

What Yang Weiqing values most is the agreement of the two sides' concepts. "Other investors just want to invest money, and I am required to form a team for product research and development, sales, etc., but management is not my specialty." The manager of this enterprise only let Yang Wei have pigging technology, and he didn't have to worry about the business of the later stage of the product. At the same time, Yang Weiqing also saw the strength of the company: backed by family businesses involved in many fields, the company has a strong ability to resist risks.

"Seeking truth from facts, professional people do professional things." Yang Weiqing proposed to himself the requirement of "three non unity", that is, "not a legal person, not a controlling shareholder, but long ago expected dividends, and one thing, one end". "Although I still hold shares in the ramie charcoal project at present, the proportion is relatively small. If there are other projects in the future, I will also adhere to the 'three nots' principle, and do not want to be distracted in scientific research or overestimate my role."

Yang Weiqing positioned himself as a "scientific research OEM" and only engaged in technology entrusted development. "'One thing, one end', my team and I only solve the scientific and technological problems for the enterprise, and take what we should take. As for how much we should take, it is up to both parties to negotiate and evaluate our intelligence, manpower and time input."

Hold up an "umbrella"

"Maybe I should concentrate on scientific research, and I also love doing scientific research." Yang Weiqing also learned that he liked scientific research when he was struggling all the way.

After graduation, he worked as a manager of chain restaurants, a lecturer of Olympic training institutions, and an Internet cafe. He always wanted to make money. In 2003, Yang Weiqing, who was already a gold medal lecturer in a training institution, earned a good salary, but he always felt that every day he was repetitive and "less interesting".

The next year, he decided to go back to school. After studying for master's and doctor's degrees at Sichuan University, he went to the United States for further study. After 10 years of secondary schooling, the 37 year old Yang Weiqing officially embarked on the road of scientific research.

Yang Weiqing envies those scholars who have chosen to do scientific research for a long time, but he knows that human experience cannot be copied. "I started late and only relied on the accumulation of time." Especially when the transformation of project components encountered difficulties in 2017 and 2018, Yang Weiqing had to make a choice, busy with work but neglected to accompany and care for his family. Whenever he thought about this, he felt deeply indebted.

It is precisely these "detours" that bring about the sharpening that makes Yang Weiqing more aware of what he wants, and also broadens his thinking and opens up the "pattern". In addition to being a university professor, Yang Weiqing also has an identity as a member of the CPPCC Sichuan Provincial Committee. His proposals are basically related to how colleges and universities get through the "last mile" of scientific and technological achievements transformation.

Having been in the rain, I want to hold an umbrella for others. Yang Weiqing's proposals always incorporate his experience after practice. He once proposed that the government could encourage universities and small and medium-sized enterprises with more flexible mechanisms to jointly build a pilot platform, and provide financial guidance, or give subsidies to the pilot stage to reduce the risk and pressure of the transfer and transformation of achievements of university research teams.

Taking stock of the obstacles encountered along the way, he suggested that from the policy level, colleges and universities should be urged to implement the evaluation mechanism that conforms to the characteristics of the transformation of scientific and technological achievements. We should not always let "only by publishing articles can we evaluate professional titles" kill the enthusiasm of college teachers and students.

Yang Weiqing wants to wade out a way. His short-term goal is to realize the industrial production of ramie carbon supercapacitors that meet commercial standards. "Now the production of ramie charcoal has increased from 100 grams to 30 tons. In the future, we will establish a formal production line with an annual output of 300 tons."

He also has a long-term plan to expand the pilot production line with an annual output of 30 to 60 tons to become a pilot technology engineering center, "making it a public and compatible pilot platform".