Silicon-carbon technology helps a series of recent smartphones achieve battery capacity of over 6,000 mAh without increasing the product size.
Smartphones are constantly upgraded in terms of configuration, camera, fast charging speed, and AI generation. However, battery technology has not made many new advances, so the appearance of silicon-carbon technology in recent phones is considered to bring novelty to the market.
Honor Magic 5, launched in 2023, is the first smartphone to use silicon-carbon batteries. Since the end of last year, a series of companies, mainly from China, have equipped their products with this solution, such as OnePlus 13 (6,000 mAh), Vivo iQOO 13 (6,150 mAh), Vivo X200 Pro (6,000 mAh), Realme GT 7 Pro (6,500 mAh), Redmi K80 (6,550 mAh) or Xiaomi 15 Pro (6,100 mAh). Meanwhile, Samsung and Apple have not joined.
According to Android Authority, silicon-carbon could be a new trend on smartphones this year when a series of smartphone manufacturers are racing to integrate it into their products.
More than 20 years of development
According to IOP Science, the first research on silicon-carbon batteries appeared in 2002, when a group of Japanese scientists published a scientific report "Coating silicon carbon as anode material for lithium-ion batteries". However, it was not until 2014 that the American company Amprius tested the production of this battery, combining silicon nanofibers and graphite to create better energy storage capacity without increasing the size of the battery.
A year later, Tesla CEO Elon Musk announced that the Silicon material in the Model S electric car battery helped increase the travel distance by 6%, but did not mention details. In 2016, a research team at Stanford University announced a method of wrapping electrodes with microscopic silicon particles in a layer of graphene to create a stable solid electrolyte with an energy density that can reach 3,300 mAh/gram.
During the period 2017-2021, a number of companies such as Global Graphene Group, Sila Nanotechnologies, Enovix, Enevate independently or jointly researched silicon-carbon batteries. Among them, Enovix (USA) provides batteries with a complete Silicon-coated anode for commercialization.
However, Group14 Technologies (USA) is the pioneer in bringing silicon-carbon to smartphones. In 2024, the company cooperated with Amperex Technology (Hong Kong) to produce and supply one million batteries using this technology for Honor smartphones, mainly in the domestic Chinese market.
Entering the smartphone market
According to TBS News, silicon-carbon batteries are basically lithium-ion batteries but have a positive electrode made of silicon combined with carbon instead of graphite. This design allows for higher energy density because silicon can hold more lithium than graphite. According to calculations, with the same size, a lithium-ion battery has a storage capacity of 372 mAh/gram, while a silicon-carbon battery is 470 mAh/gram, 15% higher.
This is clearly shown in recent smartphone models. For example, the Xiaomi Redmi Note 13 Pro+, launched in 2023, has a 5,000 mAh lithium-ion battery. But a year later, the Redmi Note 14 Pro+ generation with a silicon-carbon battery reached 6,200 mAh capacity, up 24%. Both phones have 6.67-inch screens and are almost identical in size.
Red Magic, a sub-brand of ZTE, also introduced the Red Magic 10 Pro phone late last year with a silicon-carbon battery with a capacity of 7,050 mAh. Meanwhile, the iPhone 16 Pro Max has a similar weight and size but uses a 4,685 mAh lithium-ion battery.
According to Trusted Reviews, in addition to their large capacity, silicon-carbon batteries are considered more environmentally friendly than lithium, cobalt, and nickel, which are currently present in non-renewable lithium-ion batteries. Meanwhile, silicon is an abundant resource, easy to mine, and has less environmental impact.
In theory, the energy storage capacity of silicon-carbon is 10 times greater than graphite (4,200 mAh/gram compared to 372 mAh/gram). However, using pure silicon anodes can cause extreme expansion, with the structure swelling up to 300% when fully charged, reducing its lifespan and causing structural damage.
In addition, silicon reacts strongly with the electrolyte, leading to lithium loss and reduced capacity over time. Silicon also has a lower conductivity than graphite, which can slow down the rate of charging and discharging, increasing losses due to internal resistance, which can lead to more heat and shorten battery life.
As a result, the battery performance of the new technology is currently only 10-20% higher than that of lithium-ion, depending on the silicon content.
Some companies have come up with their own solutions. Oppo uses a method of increasing the silicon content to maximize energy density using advanced techniques such as laser drilling, using improved copper foil to reduce battery size. As a result, the battery equipped on the Find X8 model has reduced the thickness from 5.87 mm in the previous generation to 5.1 mm, while increasing the capacity from 5,000 to 5,630 mAh inside the 7.85 mm thin body.
The Oppo Find N5 foldable smartphone is also equipped with a 5,600 mAh silicon-carbon battery despite the device being 4.21 mm thin when opened and 8.93 mm when folded. Vivo also uses new technology for the 5,700 mAh battery on the 5.2 mm X Fold 3 Pro foldable model. For comparison, Samsung's Z Fold 6 is 5.6mm thick but uses a 4,400mAh lithium-ion battery.
According to TechRadar, foldable smartphones will benefit the most from silicon-carbon battery technology shortly. In addition, the wave of thin and light smartphones can be fueled by this battery technology, as well as move to other types of devices such as smartwatches, tablets, and laptops.
However, the biggest problem with silicon-carbon is its lifespan. A young battery technology that has been commercialized in a short time needs more time to verify its durability. Android Authority believes that although replacing the battery of a smartphone after a period of use is inevitable, users may face this problem sooner if they use a device with a silicon-carbon battery, especially when combined with fast charging.
"It is not necessary to buy a smartphone just because it is equipped with a silicon-carbon battery, especially when you are on a tight budget," the site commented. "Due to the complex manufacturing process, the technology is currently mainly for flagship smartphones, creating attraction with the novelty factor. It may take a few more years for this technology to spread to the mid-range segment."