Today we introduce a silicon negative electrode battery company founded by Chinese people. This company often mentions in the news the companies that produce silicon negative electrode materials, and has a resounding name called California Lithium Battery, abbreviated as CalBattery. The founder of the company is called Junbing Yang, who holds the position of CTO and controls the company's technological development direction. After obtaining a PhD in Materials Science from the Chinese Academy of Sciences, Dr. Yang went to the United States for postdoctoral research and later joined the Argonne National Laboratory near Chicago, where he worked on battery research for nearly ten years.

In 2011, Dr. Yang established this startup company using his self-developed silicon negative electrode material technology. In 2014, CalBattery entered into a joint venture with another company that produces lithium iron phosphate batteries, utilizing their respective technological strengths to produce silicon negative electrode lithium cobalt oxide positive electrode polymer electrolyte batteries. The joint venture is expected to start production in 2016 and sell the above-mentioned new lithium batteries to the market. However, since then, the name of CalBattery company has basically disappeared from people's vision, and there are no further news reports on searching for the company's name.

Since CalBattery has not disclosed too many detailed details of silicon negative electrode materials, we have indirectly learned about the technologies that the company may use by consulting Dr. Yang's relevant journal papers. Overall, this technology uses sheet-like graphene material as a carrier to deposit nano silicon particles on the surface of graphene. Due to the formation of some gaps between sheet-like graphene during stacking, these gaps become the space for silicon particles to expand during battery charging, while the entire negative electrode material does not expand outward, ensuring the stability of multiple cycles. The following image is an electron scanning electron microscope photo of a silicon carbon composite material. It can be seen that silicon particles with a diameter of approximately 600 nanometers are attached to the surface of the sheet-like graphene. The density of the silicon particles can be manually adjusted to control the silicon content in the negative electrode.

The specific preparation process of the silicon negative electrode material can be explained in the following figure. The raw material starts from graphite particles, dissociates graphite into flakes of graphene at high temperatures, and then injects trichlorosilane gas to decompose it into silicon atoms and deposit them on the surface of graphene. As the amount of silicon atoms increases, the surface of graphene will be covered by nano silicon particles. Afterwards, a layer of carbon film is deposited on the surface of the silicon particles, which can protect them from direct contact with the electrolyte and fill some gaps on the graphene surface to minimize the surface area. At this point, the silicon carbon composite material has been prepared. The characteristic of this technology is the use of flat sheet graphene materials to distinguish it from the morphology of nano porous carbon microspheres or nano silicon carbon wires used in other technologies, which is a relatively rare technical form.

In Dr. Yang's paper, they attempted different silicon carbon contents, with negative electrodes containing up to 60% silicon content. The energy density of the first cycle can reach 2300mAh/g, and during high current density cycles, the energy density can stabilize at 1060 mAh/g, with no attenuation after more than 150 cycles; There are also negative electrodes with silicon content as low as 14%, as shown in the figure below. After 500 deep charge discharge cycles, 90% of the energy storage can be maintained, and its energy density is 553 mAh/g, which is about 30% higher than that of all graphite negative electrodes.

CalBattery does not have many secrets, nor does it have a grand history of financing and listing. We have analyzed the technology adopted by the company from the perspective of exploring Chinese entrepreneurship in the American battery industry, providing more feasible technical references for everyone.

**The article is for communication purposes only and cannot provide investment references. The author does not hold any company stocks mentioned in the article at the time of publication. Because the official account can't open the message function, if you have any questions or suggestions, please send a message to the official account, and we will reply as soon as possible, thank you! Scan the following QR code to follow ZH Energy Storage official account.

Reference:

1. California Lithium Battery official website www.clbattery.com

2. Nanosilicon-Coated Graphene Granules as Anodes for Li-IonBatteries, Adv. Energy Material. 1, 495-498 (2011)

3. Silicon Graphene Composite Anodes for High Energy Lithium Batteries, EnergyTechnol. 1, 77-84 (2013)

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Author Introduction:

Dr. Xie Wei, Bachelor and Master of Materials Science from Tsinghua University, and Ph.D. in Chemical Engineering from the University of Texas (Austin) in the United States. Mainly engaged in the development of energy storage batteries, has held important positions in multinational corporations and startups, led multiple research and development projects funded by the US Department of Energy, and won the 2013 US Annual 100 Best Research and Development Technology Award. Published 17 papers in top journals in materials science and energy storage, served as a reviewer for 5 international journals, and has applied for 17 international invention patents.

Introduction to ZH Energy Storage Company:

Shenzhen ZH Energy Storage Technology Co., Ltd. is committed to the research and development, promotion, and application of energy storage technology, aiming to help achieve China's goal of "carbon neutrality" through the application of electrochemical energy storage technology. In the early stages of development, the company focused on providing technical support and consulting services to the Chinese energy storage market by leveraging its accumulated industry experience and outstanding research and development capabilities in the field of energy storage. At the same time, the company focuses on conducting research and analysis on the Chinese energy storage market, and developing or introducing the most advanced and effective energy storage technologies for the Chinese market.

Company's technical research and development direction: water-based energy storage batteries, lithium-ion battery materials, fuel cells, ion exchange membranes, coatings and adhesives, membrane separation technology.

Domestic business: technical cooperation, academic exchange, technical lectures on company technology research and development, research and development consulting, and guidance on paper writing.