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Japan’s TDK claims it has made a breakthrough in the materials used in its tiny solid-state batteries, with the Apple supplier predicting a significant increase in performance in devices from wireless headphones to smartwatches.
The new material provides an energy density — the amount that can be squeezed into a given space — of 1,000 watt-hours per liter, about 100 times greater than TDK’s current mass-produced battery. Since TDK introduced it in 2020, competitors have moved on, developing small solid-state batteries that offer 50 Wh/l, while rechargeable coin batteries using traditional liquid electrolytes offer around 400 Wh/l, according to the group.
“We believe that our newly developed solid-state battery material can make a significant contribution to society’s energy transformation.” We will continue development towards early commercialization,” said TDK CEO Noboru Saito.
The batteries to be produced will be made of all-ceramic material, with a solid oxide-based electrolyte and lithium alloy anodes. The battery’s high ability to store electrical charge, TDK said, will allow for smaller device sizes and longer runtimes, while the oxide offers a high degree of stability and therefore safety. The battery technology is designed to be used in smaller sized cells, replacing existing coin-shaped batteries found in watches and other small electronics.
The breakthrough is the latest step forward for a technology industry that experts believe could revolutionize energy storage, but which faces significant hurdles on the way to mass production, especially with larger battery sizes.
Solid-state batteries are safer, lighter and potentially cheaper, and offer longer performance and faster charging than current batteries that rely on liquid electrolytes. Breakthroughs in consumer electronics have reached electric vehicles, although the dominant battery chemistries for the two categories already differ significantly.
The ceramic material used by TDK means that larger-sized batteries would be more fragile, meaning the technical challenge of making batteries for cars or even smartphones won’t be overcome in the foreseeable future, according to the company.
Kevin Shang, senior research analyst at Wood Mackenzie, a data and analytics firm, said “unfavorable mechanical properties” as well as the difficulty and cost of mass production are challenges in moving the application of solid oxide-based batteries into smartphones.
Industry experts believe that the most significant use case for solid-state batteries may be in electric cars, allowing for greater driving range. Japanese companies are at the vanguard of efforts to commercialize the technology: Toyota aims to do so as early as 2027, Nissan a year later and Honda by the end of the decade.
Automakers are focused on developing sulfide-based electrolytes for long-range electric vehicles, an alternative type of material to the oxide-based material developed by TDK.
However, there is still skepticism about how quickly the much-hyped technology can be realized, especially the larger batteries needed for electric vehicles.
Robin Zeng, founder and CEO of CATL, the world’s largest electric vehicle battery maker, told the Financial Times in March that solid-state batteries don’t perform well enough, lack durability and still have safety issues. Zeng’s CATL arose as a spin-off from Amperex Technology, or ATL, which is a subsidiary of TDK and a leading global manufacturer of lithium-ion batteries.
TDK, which was founded in 1935 and became a household name as a leading cartridge brand in the 1960s and 1970s, has a long history of battery materials and technology.
It has a 50 to 60 percent global market share in the small-capacity batteries that power smartphones, and is targeting leadership in the mid-capacity market, which includes energy storage devices and larger electronics such as drones.
The group plans to start shipping samples of its new battery prototype to customers from next year and hopes to be able to move into mass production after that.
