The top student must be diligent.

Chapter 197: Just another theory

Science Island Laboratory.

In Xiao Yi's office.

At this time, there were four people standing in front of Xiao Yi.

These four people are newcomers to their laboratory.

Three postdoctoral fellows and one assistant researcher.

"Okay, our research group consists of just a few of us."

Xiao Yi looked at the four people in front of him and said with a smile.

The four of them were all very excited. They had never dared to think about being able to work on a project with Xiao Yi before.

"You all should introduce yourselves first, so that we can get to know each other. Um... let's start with you, Tang Chunming."

Tang Chunming is the assistant researcher among them, and his professional title is equivalent to a lecturer in a university.
He nodded, and then began to introduce himself: "My name is Tang Chunming. I used to be a lecturer at Xijing Jiaotong University. I studied at Heilongjiang University for my postgraduate studies, but I thought it was too cold there..."

Everyone laughed, and after Tang Chunming finished introducing himself, the second person began to introduce himself.

And this person is Liu Xiaodong.

After completing the withdrawal procedures at Shanghai Jiao Tong University, he came here directly.

I had rented a house a few days ago, and today I officially joined Xiao Yi's research group.

"My name is Liu Xiaodong. I used to be a postdoctoral fellow at Shanghai Jiaotong University. Then I heard that Science Island Laboratory started recruiting, so I quit there and came here..."

After hearing Liu Xiaodong's self-introduction, several people showed surprised expressions.

The treatment for postdoctoral fellows at Shanghai Jiao Tong University is quite good, and it is located in Shanghai. Why would you come to a newly built laboratory?
Well...even though they themselves came.

Liu Xiaodong did not talk about his experiences when he withdrew from the competition. Instead, he seemed to be trying to gain sympathy by talking about them.

He didn't need it, and he had already expressed his gratitude to Xiao Yi when he came to the Science Island Laboratory a few days ago.

Then, the other two postdoctoral fellows also began to introduce themselves.

One is Meng Hao, from Jinling University, and the other is Chen Tao, a rare female postdoctoral fellow in science and engineering, who is from USTC and then came to Science Island Laboratory to study.

"it is good."

After they finished introducing themselves, Xiao Yi walked up to them and said, "Now let me introduce our topic to you."

The four of them immediately pricked up their ears and showed serious expressions.

As for Xiao Yi's topic, they had long wanted to know what it was.

As we all know, every one of Xiao Yi's topics is of great importance, whether in the field of mathematics or any other field.

The previous high-temperature superconductors alone are Nobel Prize-level achievements.

Xiao Yi smiled, and then said: "Our project is a solid-state lithium battery."

Suddenly, the four of them widened their eyes.

Solid-state lithium battery?

For people who study the materials, they are basically very clear about this thing.

It is a hot topic in the field of materials, and once it can be commercialized, it will also realize huge economic value.

Unexpectedly, Xiao Yi actually set his sights on this project.

"Then my goal is to directly realize lithium-sulfur solid-state batteries."

The four people were shocked again.

Solid-state lithium batteries and lithium-sulfur batteries are strictly speaking two different batteries and also two different research directions.

Solid-state lithium batteries need to solve the problem of solid electrolytes, while lithium-sulfur batteries need to solve the problem of sulfur electrodes. It should be noted that sulfur itself is an insulator, so how to make a decision in this regard is a technical difficulty.

But it's not over yet.

Xiao Yi continued: "In addition, since we want to study this, the goal must first be to make it commercially available. Of course, we can't achieve it overnight, so let's set a small goal first, which is to get the solid electrolyte first."

four people:"……"

Why does this sound so...

What about split?
Whether it is lithium-sulfur batteries or solid-state lithium batteries, they are still too far away from commercial use.

Commercial use means that it can be mass-produced at a low cost. However, all those that can be used currently are customized in the laboratory.

Now, their God Xiao wanted commercial use right away, and although he seemed to have some idea in his mind and said not to try to achieve it all at once, the small goals that followed made them crazy.

Is this Xiao Yi’s topic?
It is indeed powerful enough!
But now they really want to ask: Is it too late to leave now?
Perhaps Liu Xiaodong was trembling in his heart at this moment, thinking that it was as if he were sacrificing his life for his benefactor.

“That’s the goal of our project.”

Xiao Yi looked at the four people's puzzled expressions, smiled slightly, and said, "Of course, you don't have to worry. I have made some progress on solid electrolytes. Here, you can take a look at these experimental reports first."

Then he picked up a few lab reports from the desk next to him and handed them to the four people.

He certainly knew that this topic was difficult for these people, and he would not rely solely on his own fame to make these people believe that their topic could succeed.

This is no different from making empty promises.

Results speak louder than words.

The four of them were stunned. They didn't expect that Xiao Yi had actually prepared the data.

They took the experimental data and began to look at them.

Then, they all showed surprised expressions.

"This is... a nanoporous carbon material? Its performance is so good?"

"BET analysis shows that the specific surface area reaches 1200m^2/g, and the pore size distribution is maintained between 3-28nm, which is incredible."

"And it has such symmetrical redox peaks, with peak current densities of 1.5 mA/cm^2 and 1.4 mA/cm^2 respectively... much better than what I have seen in previous papers."

"The charge transfer resistance is 25Ω, and the capacity at 1C current density is 2300mAh/g, and..."

Looking at the various data listed in the experimental report, they couldn't help but be surprised.

All these data show the excellent performance of this nanoporous carbon.

This is absolutely top-level performance when it comes to solid electrolytes.

“How is this prepared?”

At once, the four of them looked at Xiao Yi with expressions full of curiosity.

"Nothing much. I just slightly improved the template method and activation method so that the two methods can be used together."

Xiao Yi waved his hand and said.

There are many methods to prepare carbon nanoporous materials, including template method, activation method, direct carbonization method and so on.

Among them, the template method and the activation method are the two most common ones.

His research simply combines the two.

But after hearing his indifferent tone, Liu Xiaodong and the other three didn't know what to say for a moment.

Combining these two methods... is it that easy? But no matter what, this carbon nanoporous material has given them some confidence in this subject.

After all, if the analysis report of this material is sent out, it can probably be easily published in "Nature Materials".

Of course, whether Xiao Yi is willing to submit to Nature Materials is still a question. After all, as this is a sub-journal of Nature, given that Xiao Yi publicly criticized Nature in the past, he probably has no chance of submitting to it.

Of course, Xiao Yi did not restrict them from submitting to Nature. After all, for him, it didn’t make much difference whether to submit to Nature or not. But for others, submitting to Nature or its sub-journals was considered a very important achievement.

"Professor Xiao, what are our next arrangements?"

Tang Chunming put down the report in his hand and asked.

The other three people also looked as if they were listening attentively.

Xiao Yi said: "The first thing to do next is to continue to optimize this carbon nanoporous material. In addition, we also need to try to modify and optimize our target solid electrolyte."

"The solid electrolyte I plan to study is lithium phosphorus sulfur chlorine, which is also the most promising solid electrolyte for commercialization in the current academic community. Well, I think you should be relatively familiar with this thing."

"Although the interface performance of lithium phosphorus sulfur chlorine can be enhanced to a certain extent with the assistance of carbon nanoporous materials, the problem still exists that its interface impedance is still relatively high and its ionic conductivity is still relatively low, so we need to find a modification solution that can reduce its interface impedance."

"First, we need you to do some modification experiments on doping LiI, LiN, and other high-conductivity ions."

"In addition, regarding the research on sulfur electrodes, I need you to do several electrochemical experiments on different sulfur electrodes."

"The experiment on carbon nanoporous materials, um... I'll leave it to you, Liu Xiaodong. You specialize in nanomaterials, so I believe you should have some experience in this area."

Liu Xiaodong nodded immediately: "Okay, Professor!"

He was indeed engaged in nanomaterials. After witnessing the excellent performance of this new carbon nanoporous material, he couldn't help but want to see it for himself. He didn't expect that Xiao Yi would give him this task.

"Then there is the solid electrolyte doping and modification experiment. I'll have to trouble Tang Chunming and Chen Tao to take care of it."

They both nodded.

The last sulfur electrode experiment was naturally handed over to Meng Hao.

Xiao Yi's assignments were basically in line with their past research directions, so they did not find any difficulties.

As the tasks were assigned, the experiment officially began.

Xiao Yi's task was naturally to analyze and study their experimental results, and then use his own materials to conduct continuous simulations.

This also made Xiao Yi sigh in his heart. As expected, it is more convenient to have someone under your command.

Otherwise, if he were to do so many experiments by himself, God knows how much time it would take.

Liu Xiaodong and his four colleagues were very motivated and started the experiment immediately after receiving the task.

Perhaps it was because of my confidence in this subject, or perhaps it was because I couldn't wait to use those new high-end experimental equipment.

Just like that, half a month passed quickly.

……

"Hmm... Is there no room for further optimization of carbon nanoporous materials?"

Looking at the experimental report in his hand, which was completed by Liu Xiaodong and was about some further experiments on carbon nanoporous materials, Xiao Yi touched his chin. Within the scope of his knowledge of the materials, he had not been able to find a point where he could continue to optimize through different simulations.

"Perhaps this material has reached its limit, or perhaps it is still a little short of the theoretical limit."

Xiao Yi shook his head.

Of course, the current carbon nanoporous material is already very excellent, whether in terms of ionic conductivity or interface impedance. In addition, its inhibitory effect on lithium dendrites has also reached a very excellent level.

"Then we'll leave this material as it is for now."

"Then there is the sulfur electrode... Indeed, using only sulfur as an electrode is totally undesirable."

"But the carbon sulfide cathode... has great potential."
"Then just try the carbon sulfide negative electrode."

With the activation of material control capabilities, our vision has entered the microscopic perspective of sulfur electrode samples.

Xiao Yi has now gradually become accustomed to this magnificent microscopic world. Without being too surprised, he directly began to simulate the changes to the internal structure according to his ideas.

The carbon sulfide cathode in lithium-sulfur batteries does not refer to CS2. Strictly speaking, it should be SC composite materials, which can improve the conductivity and utilization rate of sulfur, and at the same time strongly inhibit the shuttle effect of polysulfides. It has always been a research focus in lithium-sulfur batteries.

However, after some simulations, Xiao Yi still felt that there was a big gap.

"After many cycles, the quality of this type of electrode will always deteriorate and become unusable."

After the battery has been fully charged and discharged many times, the electrodes will gradually denature, causing performance to deteriorate and ultimately the battery capacity to decrease.

Just like a mobile phone battery, if it is used for too long, the battery performance will deteriorate, which will be reflected in the mobile phone in that 10 bars of power may be lost in 10 minutes.
Therefore, it is also important to ensure that the performance of the electrode does not deteriorate so easily, which puts very high demands on the design of electrode materials.

Xiao Yi pondered for a moment, and suddenly something occurred to him.

"What if we add some N elements? We use high molecular polymer materials and then vulcanize them!"

Xiao Yi searched for various related nitrogen-containing polymers in his mind, and finally, the name of a material appeared in his mind: "Sulfurized polyacrylonitrile!"

His eyes soon lit up.

As he had an idea, he simulated the SC composite material under his material control vision into vulcanized polyacrylonitrile.
Soon, its superior performance made Xiao Yi's eyes light up.

High active material utilization and almost 100% Coulombic efficiency, excellent reversibility and cycling stability…

This new carbon sulfide material immediately attracted all his attention.

At the same time, with its continuous optimization, this new material has gradually shown increasingly superior performance.

Until finally, he successfully determined what should be the best vulcanized polyacrylonitrile structure.

Soon, he withdrew from the field of material control and recorded the various key points about polyacrylonitrile sulfide. Then he sent these key points to Meng Hao, who was responsible for SC composite materials.

The next question is how to synthesize sulfide polyacrylonitrile with this structure.

However, for Xiao Yi, who has control over the materials, he only needs to keep experimenting and he will eventually find the correct synthesis method.

In this way, two of the three key technologies, carbon nanoporous materials and sulfur electrode problems, have basically been solved.

The final question is.

"Interfacial modification of lithium phosphorus sulfur chloride."

Xiao Yi narrowed his eyes.

I took a look at the experimental reports of Tang Chunming and Chen Tao, but the results of these experiments were not ideal.

Even if you master the materials, it still feels a bit difficult to know where to start.

It is believed that solid electrolytes are far more complex than nanoporous materials or sulfur electrodes.

It involves many complex fields such as ion conduction mechanism, material synthesis, interface engineering, etc., which requires interdisciplinary comprehensive research and multi-faceted optimization.

Xiao Yi closed his eyes and began to integrate all relevant knowledge in his mind.

After a few minutes, he opened his eyes again.

"Now that we have come this far, all we have to do is come up with another theory."

"Then come on!"

……

(End of this chapter)