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Japan’s TDK is claiming a breakthrough in the materials used in its small solid-state batteries, with the Apple supplier predicting significant performance improvements for devices from wireless headphones to smartwatches.
The new material offers an energy density – the amount that can be squeezed into a given space – of 1,000 watt-hours per liter, which is approximately 100 times greater than TDK’s current mass-produced battery. Since TDK introduced it in 2020, competitors have made progress, developing small solid-state batteries that offer 50 Wh/l, while rechargeable coin batteries that use traditional liquid electrolytes offer around 400 Wh/l, according to the group.
“We believe that our newly developed material for solid-state batteries can make an important contribution to the energy transformation of society. We will continue the development towards early commercialization,” said Noboru Saito, CEO of TDK.
The batteries to be produced will be made of all-ceramic material, with oxide-based solid electrolyte and lithium alloy anodes. The battery’s high ability to store electrical charge, TDK said, would enable smaller device sizes and longer operating times, while the oxide offered a high degree of stability and therefore safety. The battery technology is designed for use in smaller cells and replaces existing coin-shaped batteries found in watches and other small electronics.
The breakthrough is the latest step forward for a technology industry that experts say could revolutionize energy storage but faces significant obstacles on the path to mass production, especially with larger battery sizes.
Solid state batteries are safer, lighter and potentially cheaper, offering longer performance and faster charging than current batteries that rely on liquid electrolytes. Breakthroughs in consumer electronics have made their way to electric vehicles, although the dominant battery chemistry for the two categories now differs significantly.
The ceramic material used by TDK means that larger size batteries would be more fragile, meaning the technical challenge of making batteries for cars or even smartphones will not be overcome in the near future, the company said.
Kevin Shang, senior research analyst at Wood Mackenzie, a data and analytics company, 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 to smartphones.
Industry experts believe that the main use case for solid-state batteries could be in electric cars, as they enable longer driving range. Japanese companies are leading the way in commercializing the technology, with Toyota already targeting 2027, Nissan the following year and Honda the end of the decade.
Automakers are focusing on developing sulfide-based electrolytes for long-distance electric vehicles, an alternative type of material to the oxide-based material that TDK has developed.
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 maker of batteries for electric vehicles, told the Financial Times in March that solid-state batteries did not work well enough, were not durable and still had safety issues. Zeng’s CATL was created as a spinoff of Amperex Technology, or ATL, a subsidiary of TDK and the world’s largest producer of lithium-ion batteries.
TDK, founded in 1935 and becoming a household name in the 1960s and 1970s as a top brand for cassette tapes, has long experience in the field of battery materials and technology.
It has a 50 to 60 percent global market share in small-capacity batteries that power smartphones and is aiming for leadership in the medium-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 starting next year and then hopes to move into mass production.