Chapter 960 Porous Silicon-Based Molecular Exchange Membrane
Unfortunately, Chen Yushan guessed wrong this time.
After returning to Jinling, Lu Zhou was indeed ready to start a new round of retreat, and he did make up his mind to "never step out of the room until the Riemann conjecture is solved", but the reality is that things are really difficult. Too much.
This time it was Yang Xu, director of the Institute of Computational Materials, who called him for help.
As for the content of the call for help...
It is about the lithium-air battery project established two or three years ago.
Speaking of it, Lu Zhou was also quite surprised. Until the end of last year, he had been able to see the news about the significant progress in the research of lithium-air batteries from the report of the Institute of Computational Materials.
How come this year, the whole research has taken a sharp turn for the worse?
Let Wang Peng drive himself to the Jinling Institute for Advanced Study. As soon as Lu Zhou stepped into the laboratory, Yang Xu grabbed his arm with a painful face.
"Do me a favor! Boss! I'm already... dying!"
"Don't be like this. If you have something to say, don't I come here? Don't make it like a last word. If you have any problems, let me know. I'll see if I can help you find a way..."
Seeing Yang Xu's mentality exploded, Lu Zhou was really taken aback.
Since this guy became the director of the Institute of Computational Materials, he has led many large projects, and even solved many problems in materials science for the Jinling Institute for Advanced Study.
It's not surprising that research in such a cutting-edge field will encounter unsolvable problems, but the problem that can torture this guy like this...
To be honest, Lu Zhou was really curious.
Yang Xu: "Do you still remember the porous silicon-based molecular exchange membrane I mentioned in the research progress report some time ago?"
Lu Zhou thought about it carefully, but recalled some contents of the report, nodded and said.
"I have a little impression."
Taking a deep breath, Yang Xu continued: "According to the experimental analysis, we found that under a certain pressure difference of this type of porous silicon material, the gas on the high-pressure side can slowly transport molecules of a specific diameter to the low-pressure side. Our The project team immediately followed up this piece of research and successfully fabricated an exchange membrane capable of screening gas molecules in the 3.4-3.5A diameter range."
Lu Zhou: "Isn't that good?"
The diameter of the oxygen molecule is exactly 3.46A, which happens to be within this range fairly. Although the Ar gas molecule is 3.4, it is also close to this screening interval, but Ar is a rare gas, so it has no effect.
"It's not good at all." Yang Xu shook his head with a bitter expression and continued, "The upper and lower boundaries of the screening interval are not a fixed value, but change linearly with the air pressure...you understand."
Hearing this sentence, Lu Zhou finally showed a clear expression on his face.
"So that's it, I understand your question."
In short, this porous silicon-based molecular exchange membrane is like a fishing net full of elasticity. The bigger the net is, the bigger the mesh of the fishing net will be, and the more fish will slip through the net...
As for whether the air pressure on both sides can be maintained at a constant value to ensure that only oxygen passes through the exchange membrane...
This is obviously impossible.
Yang Xu has made it very clear that the movement of the upper and lower boundaries of the entire screening interval changes linearly with the change of the air pressure difference on both sides.
Not to mention the technical cost of controlling the air pressure difference to such a precise level, from the perspective of safety, it is absolutely impossible for them to allow the redox reaction system in the lithium-air battery to run on such an unstable steel wire .
The liveliness of lithium metal is not a joke, it is the master who explodes when there is a disagreement!
If a little bit of impurity is put in, what they make is not a battery, but a bomb.
"We've been stuck on this bottleneck for half a year," Yang Xu shook his head, "We've tried every possible method..."
Lu Zhou thought for a moment and said, "Did you do a simulation? Let me see."
"follow me."
Taking Lu Zhou to the computer, Yang Xu held the mouse and clicked twice, and soon a three-dimensional composition of a silicon-based molecular exchange membrane with a porous network superimposed structure was presented in front of Lu Zhou.
Pointing to the image on the screen, Yang Xu explained.
"We try to increase the surface pressure on one side of this exchange membrane, and molecules of a certain diameter will pass through the channels in the molecular exchange membrane at a certain rate..."
As he spoke, Yang Xu held the right hand of the mouse and tapped it twice with his index finger.
On the screen, the red and green dots distributed on the right side of the molecular exchange membrane began to gather towards the surface of the molecular exchange membrane as if they had found a pouring outlet.
"...When the surface pressure of the membrane reaches position A in the figure, oxygen begins to pass through the molecular exchange membrane and move to the gas exchange chamber of the lithium-air battery. However, when the surface pressure continues to increase with the increase of the pressure difference, it reaches position B Nitrogen will also start to pass through the exchange membrane at the same time..."
"But in fact, when the pressure difference starts to gradually change from A to B, some nitrogen molecules are already permeating inward at a slow rate."
On the screen, the red dot that marks the nitrogen gas has been in contact with the lithium negative electrode through the exchange membrane.
Watching Yang Xu simulate the demonstration on the software, a dignified expression appeared on Lu Zhou's face.
After finishing the demonstration, Yang Xu let out a long sigh and leaned back on the computer chair.
"I can think of ways to deal with a series of impurities including water molecules, carbon dioxide, and even carbon monoxide, and some gases such as sulfur dioxide with a weak content are also easy to deal with, but only nitrogen...it is too difficult to deal with It's like a swarm of flies that can't be chased away."
Even though nitrogen can usually be used as a protective gas, such as in the food industry, it cannot be used for lithium-air batteries, because nitrogen will react with lithium to form unstable Li3N.
If nitrogen gas is allowed to enter the circulation system of the lithium-air battery, the entire battery may fail after only a few runs.
The key to the difficulty of lithium-air batteries is that lithium metal is too active. And the impurities that need to be eliminated are too lazy.
At the beginning, IBM didn't believe in this evil, and invited the famous Almaden Research Center to work together on this project, and even used the distributed computing technology that now seems to have some black technology elements, positioning each one into the reaction system Oxygen atoms and precisely distribute them to the lithium anode...
As for the final result, it is also obvious.
Even the rich and powerful IBM finally had to believe in this evil, cut off the whole project like a bottomless pit, and fired the squid of the project leader.
Although the silicon material of the Institute of Computational Materials has indeed brought great success to the research in this direction, if it cannot solve the problem of eliminating the passage of other impurity gases, this can only be regarded as an interesting phased result. , no more advanced than the idea of putting an oxygen tank around the battery.
Before finding Lu Zhou, the research team of the lithium-air battery project led by Yang Xu has been stuck on this bottleneck for almost half a year, and has made no progress so far.
His intuition told him that if he couldn't do it, no one in the entire Institute for Advanced Study could hope to solve this problem, and probably only one of the founders of computational materials science—Professor Lu.
However, even though Lu Zhou was quite confident in his abilities, he couldn't think of a good solution for a while.
After rubbing his chin and pondering for a long time, he could only give an ambiguous answer in the end.
"...I'll go back and think about it, and if there's any new progress, I'll let you know."
Seeing that Lu Zhou couldn't think of a good solution, Yang Xu gradually began to sigh without any hope.
"...I thank you!"
If it really doesn't work, he can only declare that this technical route has failed, and think about other possible directions instead.
Hearing Yang Xu's "thank you", Lu Zhou didn't notice the despair in the heart of this "academic leader who has begun to doubt his life", but smiled a little embarrassedly.
"What is there to thank me for..."
If this thing can be researched, it will be a market worth tens of trillions!
Even if he is not very interested in money, the value behind this topic is worth a try...