Track Hyper | Apple's foldable device will be equipped with silicon-carbon anode batteries

Author: Zhou Yuan / Wall Street News

The Apple supply chain in mainland China and Taiwan, which supplies Apple's foldable screen phones, has begun preliminary preparations for the foldable screen phone expected to be launched in the third quarter of 2026.

In terms of batteries, the Apple foldable screen phone will use two ultra-thin silicon-carbon anode batteries with a capacity of approximately 5000mAh.

Silicon-carbon anode batteries use a composite of silicon and carbon materials as the anode material.

Carbon materials are typically used as structural supports or auxiliary components, forming composite materials with silicon, such as silicon-carbon alloys, silicon-coated carbon, and carbon-coated silicon, to improve issues like volume expansion during charge and discharge processes, enhancing the battery's cycle stability and rate performance.

The advantages of this type of battery mainly include four points: First, high energy density, with silicon's theoretical specific capacity reaching 4200mAh/g, far exceeding the 372mAh/g of traditional graphite anode materials.

By compounding silicon with carbon materials to create silicon-carbon anode materials, the energy density of the battery can be significantly increased, allowing the battery to store more energy within the same volume or weight, meeting the demand for high energy density batteries in electronic devices and electric vehicles, thus extending the usage time of devices and the range of vehicles.

Second, excellent charge and discharge performance. Silicon-carbon anode materials have a high lithium-ion diffusion coefficient, allowing lithium ions to quickly embed and extract during the charge and discharge process, resulting in good charge and discharge performance, enabling fast charging and high current discharging, improving the battery's efficiency and convenience.

Third, lower initial irreversible capacity loss: Through reasonable material design and preparation processes, silicon-carbon anode materials can reduce irreversible capacity loss during the first charge and discharge process, improving the battery's initial coulombic efficiency, allowing the battery to utilize active materials more fully during the first use and reducing energy loss.

Fourth, a higher operating voltage platform. The operating voltage platform of silicon-carbon anode materials is relatively high, generally between 0.1-0.2V (relative to Li/Li+), providing a higher battery output voltage compared to traditional graphite anode materials, thus enhancing the overall performance and energy utilization efficiency of the battery system.

There are also shortcomings, such as severe volume expansion issues, limited cycle life, complex preparation processes, and higher costs.

During the charge and discharge process, silicon undergoes significant volume changes, with expansion rates reaching 300%-400%.

This massive volume expansion can lead to structural damage of the electrode materials, worsening the contact between active materials and current collectors, thereby reducing the battery's cycle stability and lifespan.

By compounding silicon with carbon, the volume expansion issue of silicon is alleviated to some extent, resulting in relatively better cycle performance and stability of the battery.

Previously, the iPhone 17 series launched by Apple this year will also be equipped with this type of battery, thereby significantly improving the poor battery life of Apple's smartphones.

CATL provides silicon-carbon anode batteries for domestic Android phones, with multiple Android phones using this type of battery.

For example, Xiaomi's Jinsha River battery, Honor's Qinghai Lake battery, OPPO/OnePlus's Glacier battery, and vivo's Blue Sea battery, among others These names refer to different but essentially the same batteries, all supplied by Contemporary Amperex Technology Co., Limited (CATL), which was founded in 1999 by Liang Shaokang, Chen Tanghua, and Zeng Yuqun.

CATL focuses on the research and production of consumer batteries, with products including lithium batteries for mobile phones, laptops, tablets, and home energy storage lithium batteries.

The holding parent company of CATL (ATL-nd) is New Energy (Hong Kong) Technology Co., Limited (ATL), which is a wholly-owned subsidiary of Japan's TDK Corporation.

According to the information mentioned in the report titled "Report on the Learning and Investigation Trip to Fujian Province and the Conduct of Investment Promotion Activities" released by the Economic and Technological Cooperation Bureau of Guyuan City on September 2, 2019: CATL was established in 1999 and operates independently as a wholly-owned subsidiary of Japan's TDK Corporation, headquartered in Hong Kong.

TDK Corporation was established on December 7, 1935, originally named Tokyo Denkikagaku Kogyo K.K. It was officially renamed TDK Corporation in 1983.

Currently, no A-share company can provide finished silicon-carbon anode batteries, although some companies are upstream suppliers of silicon-carbon anode materials.

For example, Putailai has mass production capabilities in silicon oxide and silicon-carbon anode materials; Xiangfenghua's silicon-carbon anode material products have reached industrialization conditions, and the products supplied are used by LG Chem in the Tesla Shanghai factory project.

Shida Shenghua plans to invest in a 1,000 tons/year silicon-carbon anode material project and has certain technical and production capacity reserves in the silicon-carbon anode material field; Silibase Technology has built a pilot production line with a capacity of 50 tons/year for silicon-carbon anode materials and has sent samples to several battery manufacturers for joint development.

It should be said that the performance boost for upstream material suppliers from downstream terminal manufacturers using large silicon-carbon anode batteries is relatively indirect, but the market's understanding and choices are often unexpected, which is the charm of the A-share market.

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