The Science Fiction World of Xueba

A week later, Jiangcheng University officially announced the establishment of a lithium-air battery research team, with Pang Xuelin as the team leader and Kirton Walker as the deputy team leader.

At the same time, Xinkai Material Technology Co., Ltd. announced that it will provide 100 million RMB financial support for the lithium-air team.

In addition, Pang Xuelin mortgaged his villa in Binjiang and obtained a low-interest loan of 50 million yuan from the bank.

It can be considered as a fund of 150 million RMB.

Next, what Pang Xuelin and the others have to do is to manufacture a prototype of a lithium-air battery in the laboratory.

At this time, in the conference room of the School of Chemistry and Molecular Engineering of Jiangcheng University, besides Pang Xuelin and Kirton Walker, there were six or seven scholars transferred from the School of Materials Engineering and the School of Chemistry and Molecular Engineering.

These people were basically recommended by the school, and after a joint interview with Pang Xuelin and Kirton Walker, they were approved by the two and joined the lithium-air battery project.

The outside world is not optimistic about the lithium-air battery project team.

During this period, the bet between Pang Xuelin and Tian Hong on lithium-air batteries also spread abroad.

Foreign media ridiculed that the actions of Pang Xuelin and Cotton Walker were just another technical scam.

Even many well-known scholars in the field of lithium batteries have stood up and said that although lithium-air batteries have a good prospect, the current research is still quite elementary, and there are still many challenges in the field of science and engineering that need to be solved. If you want to really enter the practical application, It will take at least ten years.

The reason why Pang Xuelin bet with Tian Hong to produce a lithium-air battery within half a year was just a dispute of pride.

However, these scholars who joined the lithium-air battery team were not influenced by too much public opinion, but were eager to try the next research.

The contact in the past week, and some technical routes revealed by Pang Xuelin, have made them realize that Pang Xuelin and Cotton Walker's attempt in the field of lithium-air batteries is not a fantasy, but a real possibility.

Moreover, the 150 million funding invested by Pang Xuelin also made them full of confidence in the next research plan.

Pang Xuelin sat at the top of the conference room, looked at the crowd, smiled slightly, and said: "The first meeting of all members of the lithium-air battery project is starting now. Today we will make a detailed report on the specific implementation route and project division of lithium-air batteries. Detailed task assignment plan."

Pang Xuelin paused and continued: "With the development of science and technology, energy shortage has become an urgent problem to be solved. So people began to pay more and more attention to environmentally friendly batteries with high energy storage. The research on batteries has developed from Ni-MH to the present. Lithium secondary battery. The volume ratio, energy ratio and mass ratio of lithium secondary battery are all high, there is no memory effect of Cd-Ni sintered battery, there is no problem of battery capacity loss, and the battery does not contain lead, cadmium, mercury, etc. Harmful substances are called green batteries. Therefore, lithium secondary batteries have become a research hotspot in the world today due to their obvious advantages such as high energy density, long cycle life, green and pollution-free."

"And lithium-air batteries are the most advanced among lithium secondary batteries. However, lithium-air batteries still have the following problems."

"The first is the problem of lithium crystal dendrites. As we all know, lithium-air batteries generally use lithium metal as the negative electrode material. When metal lithium is charged, due to the uneven surface of the lithium electrode, the electrical signal distribution on the surface of the lithium battery is uneven, causing lithium unevenness. Uniform deposition. This non-uniform deposition process causes lithium to deposit too quickly in some places,

Dendrite-like crystallization occurs, that is, lithium dendrite phenomenon. When the lithium crystal dendrites develop to a certain extent, there will be two consequences, one is that the crystal dendrites break, resulting in dead lithium phenomenon, resulting in irreversible lithium; the other is more serious consequences, the crystal dendrites pass through the separator and connect the positive and negative electrodes , Forming a short circuit of the battery, resulting in a large current, generating a large amount of heat, the temperature rises sharply, causing the battery to catch fire, or even explode, resulting in serious safety problems. "

"Second, the problem of moisture and nitrogen control in the air. Lithium-air batteries are an open system, which is different from lithium-ion batteries. Lithium-air batteries use oxygen in the air, while air contains nitrogen and water vapor. Reacts to both. To be oxygen permeable and nitrogen and water resistant is a difficult problem to solve.”

"Third, there is the problem of accumulation of solid reaction products. Since the oxygen in the air is used as the active material on the positive electrode of the lithium-air battery, the capacity density of the positive electrode is theoretically infinite, and the capacity can be increased. In addition, if the negative electrode uses lithium metal, The theoretical capacity will increase by a single digit compared with lithium-ion rechargeable batteries. However, the solid reaction product lithium oxide (Li2O) will accumulate on the positive electrode, blocking the contact between the electrolyte and the air, causing the discharge to stop."

"Fourth, the catalytic reduction of oxygen. The reaction speed of oxygen is very slow. To improve the reactivity of oxygen, high-efficiency catalysts must be used. The current catalysts are all noble metals. Therefore, it is necessary to develop efficient and cheap catalysts, which has always been a constraint. The short board of fuel cell development."

"These four issues will be difficult problems that we need to solve urgently in the next six months."

"At present, we mainly have the following ideas about these issues."

"First, the problem of lithium dendrites. At present, there are two main solutions to the problem of lithium dendrites in the world. The first one is to use heavy magnesium carbonate (trifluoromethanesulfonyl) as an electrolyte additive to make the deposited magnesium and The subsequently accumulated lithium undergoes an alloying reaction. The second is to use a 3D polydimethylsiloxane (PDMS) layer or a silicone resin layer as a substrate for the lithium metal anode to alleviate the formation of lithium dendrites. But these two There are more or less certain problems in the schemes. Therefore, I consider covering the surface of lithium metal with a large-scale single-layer graphene film, thereby inhibiting the generation of lithium dendrites. As for how to cover the surface of lithium metal with graphene film, This problem will be handed over to the joint team of Professor Ye Xingmin and Professor Huo Ziqian to solve!"

"Professor Pang, don't worry, we promise to complete the task."

Both Ye Xingmin and Huo Ziqian nodded in agreement.

Both of them are from the School of Materials Engineering. Ye Xingmin joined Pang Xuelin's research group last year and played an important role in the process of preparing high-purity single-walled carbon nanotubes in the laboratory.

Later, Pang Xuelin was transferred to the Flying Blade Materials Project Team, and his rank was upgraded from an associate professor to a professor.

At present, the flying blade material project is progressing smoothly, and Pang Xuelin simply got Ye Xingmin to the lithium-air battery project team.

Ye Xingmin has cooperated with Pang Xuelin for the longest time, and he has already experienced Pang Xuelin's academic level before. Therefore, among the people present, Ye Xingmin has the most confidence in Pang Xuelin.

As for Huo Ziqian, he is an expert in the field of graphene materials. Pang Xuelin's large-scale single-layer graphene material preparation and industrial production plan has already made him amazed.

This time Pang Xuelin invited him to join the lithium-air battery project team, and he readily agreed.

Pang Xuelin smiled slightly, took a sip from the teacup on the table, and continued: "The second problem is the control of moisture and nitrogen in the air. This problem must be solved together with the problem of the accumulation of solid lithium oxide reaction products. After my discussion with Professor Wharton, there is the following plan: the negative electrode uses an organic electrolyte containing lithium salt in combination. Although the organic solvent cannot be discarded, the method of use is limited. The positive electrode uses an aqueous electrolyte Alkaline water-soluble gel, combined with a positive electrode formed by micronized carbon and a low-valent oxide catalyst. In a lithium-air battery, it is not solid lithium oxide generated due to the discharge reaction, but is easily dissolved in the aqueous electrolyte (Lithium hydroxide). Lithium oxide will not cause the work to stop after the accumulation of lithium oxide on the air electrode. Water and nitrogen will not pass through the partition wall of the solid electrolyte, so there is no danger of reacting with the lithium metal of the negative electrode. And , when charging, if a positive electrode dedicated to charging is configured, it can also prevent the corrosion and aging of the air electrode caused by charging."

"The only problem now is how to make the organic electrolyte containing lithium salt in the negative electrode and the aqueous electrolyte used in the positive electrode not interfere with each other and live in harmony, and at the same time ensure that lithium ions can normally shuttle between the two electrolytes. .Our method is the same as before, and we also use a large-scale single-layer graphene material as a shield between the two electrolytes. And I have calculated that the six-membered carbon ring of graphene is just enough for lithium ions to Shuttle through this channel, as long as we verify this in the experiment, then the biggest technical problem in lithium-air batteries will be solved."

"Therefore, this problem will be solved by Professor Kirton Walker and Professor He Wenyan."

After Pang Xuelin finished speaking, except for Cotton Walker who already knew the inside story, everyone else showed surprise on their faces.

Even those professors from the School of Chemistry and Molecular Engineering who collaborated with Pang Xuelin for the first time showed suddenly enlightened expressions on their faces.

No wonder Pang Xuelin dared to make this bet with Tian Hong, the key point turned out to be here.

When Pang Xuelin chatted with them before, although he revealed some information, it was far less detailed than this time.

They did not expect that Pang Xuelin and Ke Dun already had a complete idea to solve the problems of nitrogen, water reaction and solid product accumulation in lithium-air batteries, and even had a specific implementation plan.

However, they won't gossip around. The main members who joined the project team all signed non-disclosure agreements, and the penalty for breach of contract was astonishingly high.

No one would joke about their own future.

At this time, a professor named Qiu Qiwei from the School of Chemistry and Molecular Engineering praised: "Professor Walker, no wonder Professor Pang is willing to invest in your project. It turns out that you have such an ingenious solution."

Kirton Walker shook his head with a wry smile, and said, "Professor Qiu, you are praising the wrong person. I am not the designer of this plan. When I first found Professor Pang, I just felt that graphene materials have certain potential. It can be applied to the field of lithium-air batteries, but I still have a dark eye on how to realize it. This solution was proposed by Professor Pang Xuelin, and even the previous theoretical calculations were completed by Professor Pang Xuelin independently. What we will do next It’s just repeating the ideas of Professor Pang Xuelin.”

After Kirton Walker's words fell, everyone present couldn't help but looked at each other in blank dismay.

Ye Xingmin, who had been in contact with Pang Xuelin the longest, reacted a little more calmly.

This has always been Professor Pang's routine operation.

He Wenyan on the side exclaimed: "Professor Pang, do you still have research in the field of lithium-air batteries?"

Pang Xuelin said with a faint smile: "About the lithium-air battery, in fact, Professor Walker didn't look for me. I already had some ideas before, but Professor Walker came to me and said to use large-size single-layer graphene as the semi-conductor between the positive and negative electrodes. The transmembrane coincides with my thoughts, so I brought Walker here. There is a little bit of research, but they are all immature ideas. When I did research on mathematical conjectures before, when I didn’t go well or had no ideas, I just I will read some miscellaneous papers. I read a review of lithium-air batteries before, and I think this kind of battery is quite interesting. So I gathered some messy ideas before and made everyone laugh.”

He Wenyan looked at Pang Xuelin with a strange expression.

He didn't have much contact with Pang Xuelin, and his understanding of this young genius was limited to praise from others and reports in the news.

Previously, Pang Xuelin worked on carbon nanomaterials across industries, and not long ago he created artificial intelligence MOSS. These are already amazing.

Unexpectedly, the other party has such profound attainments in the field of lithium-air batteries.

The expressions on other people's faces were also similar to those of He Wenyan. After a week of contact with Pang Xuelin, they all had the feeling of knowing Professor Pang for the first time.

Pang Xuelin smiled and said: "Okay, next, let's talk about the fourth question, how to increase the reaction rate of oxygen and lithium metal. Generally, we will use noble metals as catalysts, but considering mass production and future costs The problem is that we need to find a relatively cheap metal catalyst. According to my previous theoretical calculations, we can consider choosing among metal cluster catalysts. As we all know, the chemical characteristics of the cluster show that the atoms or molecules of the cluster The increase of the number n produces odd-even oscillation and magic number characteristics. The difference of the reaction rate constant of metal clusters at different n values ​​can reach 10^3. Regarding the catalytic performance of metal cluster catalysts, one’s homonuclear and heteronuclear As a catalyst, clusters have high activity and selectivity in redox reactions. This issue is left to Professor Qiu Qiwei and Professor Xu Ting!"

After hearing the words, Qiu Qiwei and Xu Ting both nodded and agreed.

Pang Xuelin said: "About the general technical plan and route of lithium-air batteries, that's all. Do you have any questions?"

At this time, Xu Ting, who had been silent until now, said: "Professor Pang, if we use metal cluster catalysts, where should the catalyst be placed? If we put it directly in an alkaline water-soluble gel, it may cause oxidation. Lithium accumulates on its surface, which affects the charging effect and service life of the electrolyte."

Pang Xuelin smiled slightly, and was prepared for this question, and said: "It's very simple, we can directly fix it on the air electrode material made of graphite, so that not only will it not affect the electrolyte, but also pass Regularly replace the positive electrode material to solve the problem of solid reactant accumulation!"

Xu Ting nodded and said, "Professor Pang, I understand."

"Okay, do you have any questions?"

Pang Xuelin looked around.

Everyone looked at each other and said one after another: "It's gone!"

"No problem."

"I think the current plan is perfect. The next step is to see how the experiment works. When there are problems in the experiment, we can discuss and solve them at that time."

Pang Xuelin nodded and said: "Okay, since that's the case, let's leave everyone, and then officially start the project process!"