The 1,000-ton industrial demonstration of the hard carbon negative electrode of CARMERY US is being established and is expected to be completed and put into operation in mid-August.

CARMERY New Materials (Huzhou) Co., Ltd. is an innovative enterprise dedicated to carbon-based energy storage material solutions, integrating R & D, production and sales, located in Changxing County, Huzhou City, Zhejiang Province. The company is oriented to energy storage, electric vehicles, industrial vehicles, two-wheelers and base stations and other application scenarios, with lithium-ion batteries, sodium-ion battery negative materials as the main direction, according to user needs to provide high capacity, high rate, long life and low-cost hard carbon materials. The company's core personnel from the Chinese Academy of Sciences, Shanxi Coal Institute, is a systematic and institutionalized "scientist engineer" team, technical backbone in the field of carbon materials and electrochemistry for many years, solid basic research, engineering experience. Relying on the Shanxi Coal Chemical Institute of the Chinese Academy of Sciences, it has a complete basic research, material pilot development, device assembly and performance evaluation platform, which can provide customized material application solutions.

The following is a transcript of the interview:
Q: Among the hard carbon precursors, biomass, anthracite and phenolic resin will be the mainstream in the future. Which precursor does your team use?
Chen: At present, biomass precursor is the mainstream, represented by Kolali Company, which uses coconut shell. Of course, our country will also use some other biomass: starch, lignin, bamboo, fruit shell, etc., its raw materials are easy to obtain, the production process is relatively simple.
The mainstream of the future, we think is mineral raw materials. Because considering the reliability and stability of the source is relatively high, this is a direction in the future. From the perspective of cost reduction, or the reliability of the supply chain, it is more secure.
As for phenolic resin, the performance is very good. But the cost is high, affecting the promotion. At present, sodium and lithium are both pursuing high cost performance.
These materials are used by our team. However, phenolic resin, we take into account the cost-effective problem after amplification, did not do it again. The rest of our team is doing it, and according to the needs of downstream users, we provide corresponding precursors and formulate corresponding processes. Everything we do is based on the needs of the client to do product design, and we do not exclude any kind of material. Sometimes we also make a mix of multiple precursors.
Q: How does your team strengthen the sodium storage performance of anode materials and what are the test results?
Chen: In terms of sodium storage performance, we try our best to maintain the hard carbon structure, prevent ordering, form a highly disordered "house of cards" structure as far as possible, and at the same time increase the layer spacing to more than 0.38 nanometers. In the design of individual products, the closed-hole sodium storage will be realized through the hole design to increase the capacity.
On the one hand, the sodium storage capacity comes from the slope area (adsorption), and the dynamic response is better. On the other hand, it comes from the interlayer sodium embedding. This part uses the interlayer spacing to increase the interlayer spacing, reduce LC and LA (crystallite size), and make it disordered. There is also a closed-cell filling, which is a three-stage mechanism. The slope area belongs to the part of the capacity with better dynamic performance and better rate performance. We believe that we need to occupy a certain proportion, or a little higher, in order to fully reflect the advantages of high rate and low temperature of hard carbon. Of course, all this is based on the needs of users, different scenarios, user needs are different. Therefore, the proportion of each paragraph has been adjusted and changed.
As far as the test results are concerned, on the whole, the biomass system, our conventional products can achieve 300-320 mAh/g, the first efficiency can achieve more than 90%, and the comprehensive performance is good. At present, the high-capacity model can achieve a maximum of 340 mAh/g, the first 88%. For mineral systems, we can achieve 320 mAh/g, the first efficiency is 91%, and the compaction density will be higher.
Q: What do you think are the technical defects of hard carbon as a negative electrode in the market? How to solve the problem of low compaction of hard carbon technically?
Chen: To solve the problem of low compaction: one is on raw materials. Generally, this kind of mineral series, like coal and asphalt, has a higher compaction density. The second is to improve the compaction density of the pole piece as much as possible through the control of the grain size. The third is the design of the structure.
Q: What stage has Guoke Carbon America reached in the industrialization of hard carbon negative electrodes?
Chen: We have completed the 10-ton pilot test and are now doing a thousand-ton industrial demonstration. Engineering design is currently under way and is expected to be completed and put into operation in mid-August.
Q: What is the cost limit after mass production of hard carbon negative electrodes?
A: At present, after the kiloton demonstration line is put into operation, the cost of biomass should be 4-50000/ton. The mineral series can be 1-15000 lower than biomass.
Q: In addition to the electrode material itself, what is your team's research on the matching of electrolyte, diaphragm and hard carbon materials for sodium ion batteries?
A: Because we want to form a material solution, we still need to export some supporting technologies. Including the matching electrolyte, and what kind of positive electrode to match, including the corresponding binder, there are some studies on the sodium storage mechanism of hard carbon, and some kinetic studies. We still do a lot of work. Because there are many graduate students, these graduate students are still doing research closely around the industrial development of hard carbon, as well as some common key scientific issues in the application process, so that we can know what it is, and at the same time, we can also know why. At the same time, it also enables us to constantly explore the boundaries of sodium storage performance of hard carbon. In addition, from the perspective of the system, to think about the new type of hard carbon materials into the system, the interaction of some other systems or units.