Chapter 248

Friday, Xu Qingzhou came to the Jingda Optoelectronics Laboratory, which he hadn't visited for two months.

Only Gong Yunfei was in the office.

"Junior brother."

Senior brother Gong was more enthusiastic than before, holding Xu Qingzhou's hand and touching it non-stop, making him get goosebumps; the fear of being dominated by the private message wanting in-depth exchange a few days ago surged up again.

"Senior brother Gong, you this..." Xu Qingzhou retreated two steps unobtrusively, but his hand was still grabbed by Gong Yunfei.

Gong Yunfei smiled hehe, "Just want to touch the fairy spirit of the study god."

Before, there would be pressure in front of this junior brother Xu, but now pressure, what pressure, it doesn't exist at all; as long as you don't compare, there is no harm.

"Alright, Xiao Gong, hurry up and let go of your junior brother." Professor Zhao walked out of the experiment.

After 10 minutes, a girl walked in, holding a stack of magazines in her hand, separated two and placed them on the table at the door, "Senior brother Gong, this is the latest issue of 'Physics Reports'."

Read! {

"In here, there are two papers that are Xu Shen's." The girl's eyes were full of worship, afraid of disturbing Xu Qingzhou, she lowered her volume.

Xu Qingzhou smiled; let alone this small battery exploding, he had even seen the big scene where the entire laboratory exploded.

Xu Qingzhou sat down in front of the computer and opened the hard drive; inside were the experimental data of this period, and besides the experimental data, there was more comprehensive experimental information.

Xu Qingzhou nodded slightly; the lithium embedding potential of silicon is relatively high, which to a certain extent helps to avoid the formation of lithium dendrites, but silicon will undergo huge volume expansion during the charging and discharging process.

Xu Qingzhou looked up, pulled his thoughts out of various data, glanced at the journal in Gong Yunfei's hand, and remembered that the editorial department replied to the email a few days ago, saying it had been published.

Inside the laboratory, the familiar "buzzing" sound of equipment operation was ringing; Hong Yayu was in front of the X-ray diffractometer (XRD), collecting data for sample No. 138.

All the words in Gong Yunfei's heart gathered into one sentence: Junior brother is awesome.

It is necessary to perform functional analysis, using linear functions, polynomial functions, etc., to analyze battery performance parameters, such as capacity, voltage, resistance, and their changing trends with cycle times or time.

"..."

Drying and compaction.

Professor Zhao first handed Xu Qingzhou a stack of materials and said: "You should know that what we chose this time is a new type of silicon-based negative electrode material; in these two months of experiments, there is actually a common problem—too much lithium precipitation."

After reading the materials, he actually had a general understanding of the experiment; although Professor Zhao and the others had made considerable progress, there were still many problems to face.

If it were him, two top journal publications, he would have already booked a restaurant, called friends, and prepared to have a good time.

Assembly with positive electrode materials.

Next, Professor Zhao told Xu Qingzhou in detail about the progress of the project.

!.

"Moreover, in mathematics, it is definitely not as good as professionals like you."

This money seems like a lot, but once raw material procurement, equipment purchase, business trips, and labor are thrown away, it is really not enough to solve big problems like lithium dendrites.

In the morning, Xu Qingzhou basically spent time reading materials, went to the cafeteria for lunch with Gong Yunfei and the others, and in the afternoon, he didn't rush to organize data, but followed Wang Wei into the laboratory.

Xu Qingzhou narrowed his eyes, thinking about how to solve it.

"Senior brother still has something?"

Xu Qingzhou is also very clear about his work.

For example, silicon nanoparticles can to a certain extent alleviate the volume expansion effect that occurs when silicon materials themselves embed and de-embed lithium, but the specific surface area and surface energy have both increased.

Gong Yunfei was stunned for a moment, opened the latest "Physics Reports", looked down the directory, sure enough, Xu Qingzhou's name was written behind both papers.

"Xiao Xu, sit down first, let me tell you about the situation of the experiment."

Wang Wei and Xu Qingzhou were wearing goggles, and were making sample No. 139.

"Good, thank you." Gong Yunfei was processing data, looked up, saw the girl looking at Xu Qingzhou who was deep in thought in front of the computer further inside, wanting to speak but stopping, he shook his hand and smiled: "Hi, are you fascinated?"

Want to see the experimental process. Install Celgard diaphragm, inject ethylene carbonate electrolyte containing lithium hexafluorophosphate.

"Our research group can actually do this aspect, but because the direction was wrong a few days ago, our progress is much slower than planned; if we disperse manpower again, the progress will be dragged down."

"This time, we chose high-purity nano-silicon as the negative electrode active material." Wang Wei explained to Xu Qingzhou while operating.

This volume change led to the accumulation of internal stress in silicon particles, causing the silicon material to pulverize, which in turn may aggravate the formation of lithium dendrites.

"..." Looking at Xu Qingzhou's calm expression, Gong Yunfei's throat moved, and he also wanted to speak but stopped.

Conductive agent acetylene black, binder CMC, then mixed in a certain proportion.

"Of course, we were well prepared for this situation, so in subsequent experiments, we will nano-ize silicon particles, which effectively alleviates the volume effect of silicon negative electrode materials during lithium de-embedding."

"Don't have pressure, our goal is to improve the thermal stability and energy density of the battery; as long as it can be improved by 2%-4% compared to the market, we can conclude the project."

Gong Yunfei stayed next door to clean and filter the data.

Professor Zhao handed the hard drive to Xu Qingzhou, and after explaining the experimental tasks to the three students, he left the laboratory first to busy himself with other things.

Your look of complete indifference makes me a bit hurt.

Xu Qingzhou nodded; this project of Professor Zhao is funded by two companies, but the funding seems to be only about 5 million.

Of course, it is mainly Wang Wei operating, and Xu Qingzhou is observing from the side.

An unremarkable battery appeared in front of Xu Qingzhou.

Then use a coating machine to evenly coat the negative electrode slurry on the copper foil current collector to form a coating of a certain thickness.

"Junior brother, you... made two more SCIs?"

That is to say, electrochemical agglomeration is prone to occur during the charging and discharging process, and then the contact amount with the electrolyte increases, consuming a large amount of lithium ions, thereby reducing cycle performance and capacity retention rate.

Professor Zhao chuckled, "Those lithium dendrite problems and diaphragm problems, our funding and manpower can't handle them either, they are not in the scope of consideration."

"Hmm, yes, the result of my last experiment."

"Nano-ization can be divided into zero-dimensional nano-ization, one-dimensional nano-ization, and two-dimensional nano-ization." Xu Qingzhou recalled the materials he saw these two days.

"It's okay."

Two top journals can no longer cause the slightest emotional fluctuation.

It is also necessary to establish electrochemical models, thermal models, and mechanical models describing the stress-strain relationship and mechanical failure mechanism of materials during the charging and discharging process.

No, two top journals.

"Professor." Xu Qingzhou finally got rid of Senior brother Gong.

Alright, this might be a great god.

Professor Zhao showed an appreciative look; it can be seen that this young man has seriously read the materials in this area.

"Good, I'll read the materials first."

On this side, Wang Wei carefully connected the BTS-5V3A-S1 charge-discharge tester, and seeing Xu Qingzhou hadn't spoken, joked: "Don't worry, it won't explode."

Xu Qingzhou flipped through the materials in his hand and smiled: "I will do my best."

Speaking to the end, Professor Zhao sighed: "Data analysis and processing is the bridge connecting experimental data and experimental conclusions; through effective processing of experimental data, the changing laws of battery performance can be revealed, providing data support for further optimizing battery design."

Wang Wei chatted with Xu Qingzhou while paying attention to the data on the screen: "At a 0.2C charge-discharge rate, the capacity decay is slow; after 20 cycles, the capacity is still stable at 3500mA·h/g, and the capacity retention rate is maintained at about 75%."

"Currently, we have produced sample No. 109, which uses chemical etching technology to prepare boron-doped porous silicon nano-silicon; at a charge-discharge current of 2A/g, it can still maintain a capacity of 2000mA·h/g after 250 cycles."

"Continue the experiment, we will definitely be able to get the results we want."

Wang Wei is very confident, Xu Qingzhou nodded, feeling there is no problem; results are all piled up from bit by bit of experiments.

(End of chapter)