SoftBank Group Corp.’s telecoms arm is considering using battery technology from Japanese startup 3DOM Inc. as the investment giant pushes further into wireless communications projects that use flying devices, according to the battery-maker.

3DOM’s technology will likely be used for future mobility applications that require high-battery capacity, such as flying taxis or drones, 3DOM Vice President Shusuke Oguro said.

3DOM is working on lithium-metal batteries, which are more energy dense and charge much faster than lithium-ion batteries. Last month the seven-year-old firm announced plans to list in Singapore via a reverse takeover of restaurant operator Chaswood Resources Holdings Ltd.

“We are in contact with 3DOM but not able to comment in further detail,” said a spokesman for SoftBank Corp., the Japanese technology conglomerate’s publicly traded telecom unit.

SoftBank’s interest in high-power batteries is part of Masayoshi Son’s ambition to get ahead in the race toward 6G.

In March, the firm teamed with U.S.-based Enpower Greentech Inc. to develop technologies for lithium-metal batteries that may be applied in cellular base stations, and it has plans to deploy drones that would serve as base stations for mobile phones when natural disasters damage those on land.

One big drawback of lithium-metal batteries, however, is that as the battery charges, lithium ions can form spiky structures on the anode called dendrites. These dendrites can grow long enough to reach the other electrode and short circuit the battery, potentially causing a fire. The problem is more significant for lithium metal than for other anode materials like graphite.

To that end, 3DOM is developing polyamide separators for lithium-metal batteries that decrease the possibility of punctures and short circuits. Polyamide is a material that can withstand extreme heat.

The company’s public debut, which should occur by March, will allow it to more easily fund mass production of the separators, Oguro explained.

“It’s about thinking outside of the box,” said Oguro, who worked on lithium-ion battery development at Panasonic Corp. for around 35 years, in an interview. When 3DOM founder Kiyoshi Kanamura first presented the solution over a decade ago, “people said the separators would be hard to mass produce. For me, this is a big turning point.”

Scientists around the globe have for years been looking at ways to solve the dendrite issue in the hope of developing more powerful electric-car batteries.

Harvard University Associate Professor Xin Li, who heads up a research group that focuses on the design of next-generation energy storage materials, wrote in an article published in May that multi-layer battery designs allowing dendrites to be contained do exist. But he noted that there’s a “long way to go” to commercialize the technology and that scaling up is important.

3DOM’s separator has tiny holes that let ions flow smoothly, thus making uniform chemical reactions and allowing better dendrite control. The separator is soft and bendable and less costly to make than ceramic versions, Oguro said.

The company, which has received around ¥8.1 billion ($74 million) in financing from angel investors whose names it hasn’t disclosed, has recruited about 90 engineers from companies including Panasonic, Nissan Motor Co. and Honda Motor Co.

3DOM isn’t the only battery-maker developing lithium-metal cells. QuantumScape Corp., which counts Volkswagen AG and Bill Gates as backers, is developing solid-state lithium-metal batteries that replace the polymer separator with a solid-state separator that prevents dendrites. Cuberg Inc., which was acquired by Sweden’s NorthVolt AB in March, has a battery based on a non-flammable electrolyte combined with a lightweight lithium metal anode.

Oguro said 3DOM plans to start mass producing its separators later this year and begin making batteries that use the separators by the end of 2022.

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