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Japan’s TDK is claiming a breakthrough in the materials used in its tiny solid-state batteries, with the Apple supplier predicting significant performance gains for 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 more than TDK’s current mass-produced battery. Since TDK introduced it in 2020, competitors have moved forward to develop small solid-state batteries that offer 50 Wh/L, while rechargeable coin batteries using traditional liquid electrolytes offer about 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 to develop towards early commercialization,” said TDK CEO Noboru Saito.
The manufactured batteries 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, would enable smaller device sizes and longer operating times, while the oxide offered a high degree of stability and thus 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 tech industry experts who think it could revolutionize energy storage, but face significant hurdles 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 trickled down to electric vehicles, although the dominant battery chemistries for the two categories now differ substantially.
The ceramic material used by TDK means larger-sized batteries would be more fragile, meaning the technical challenge of making batteries for cars or even smartphones won’t be overcome any time soon, the company says.
Kevin Shang, principal 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 to moving solid oxide battery applications into smartphones.
Industry experts believe that the most significant use case for solid-state batteries could be electric cars by enabling greater range. Japanese companies are at the forefront of the push to commercialize this technology: Toyota is already preparing for 2027, Nissan a year later, and Honda by the end of the decade.
Automakers are focusing 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, especially the larger batteries needed for electric vehicles, can be realised.
Robin Zeng, founder and chief executive of CATL, the world’s largest electric car 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 was created as a spin-off from Amperex Technology, or ATL, which is a subsidiary of TDK and the world’s leading manufacturer of lithium-ion batteries.
Founded in 1935 and established as a premium cassette tape brand in the 1960s and 1970s, TDK has years of experience in battery materials and technology.
It has a 50 to 60 percent global market share of 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 sending samples of its new battery prototype to clients from next year and hopes to be able to move into mass production after that.