Battery that will power your phone for 'twice as long' available next year

MIT spinout SolidEnergy Systems plans to release the first of its super-long life, lithium-ion batteries in November for drones, followed by phones next year.
Written by Liam Tung, Contributing Writer

SolidEnergy's lithium metal battery has a higher capacity battery than the iPhone 6, but is half the size.

Image: SolidEnergy

New higher-capacity, lithium-ion batteries will soon be available and could keep devices running for twice as long, according to the technology's inventor.

The batteries, produced by MIT spinout SolidEnergy Systems, differ from standard lithium-ion alternatives in that they use lithium-metal foil instead of graphite as the anode material. Since the metal foil can hold more ions, it can achieve a higher energy density, which could translate into longer-lasting wearables, phones, cars, and drones.

"With two-times the energy density, we can make a battery half the size, but that still lasts the same amount of time as a lithium-ion battery. Or we can make a battery the same size as a lithium-ion battery, but now it will last twice as long," Qichao Hu, CEO of SolidEnergy, told MIT News.

According to Hu, SolidEnergy's first batteries are for drones and will be available this November. SolidEnergy also plans to deliver batteries for smartphones and wearables in early 2017 and electric cars in 2018.

Hu co-invented the battery while completing a post-doc at MIT, which led to a series of awards and the creation of the company in 2012. SolidEnergy has raised $16.5m through two funding rounds, which includes $12m in financing last year after Hu demonstrated a prototype of a battery that was half the size of the one used in the iPhone 6, but with a capacity of 2.0 amp hours, versus the iPhone 6's 1.8 amp hour battery.

SolidEnergy had for several years shared a space at the Waltham, MA facility of lithium-ion battery maker A123, but last year moved into its own, much larger facility in nearby Woburn, where it's producing its batteries.

Hu has high hopes for his battery's potential in electric vehicles, claiming it could achieve what Tesla has yet to -- allow a vehicle to drive 400 miles on a single charge. Tesla CEO Elon Musk earlier this year said it could make a 400-mile battery today, but that it needed to cut the cost per unit of energy of battery packs to make the technology affordable. Instead, Tesla is targeting a 500-mile battery in 2025.

"Industry standard is that electric vehicles need to go at least 200 miles on a single charge," said Hu. "We can make the battery half the size and half the weight, and it will travel the same distance, or we can make it the same size and same weight, and now it will go 400 miles on a single charge."

According to MIT, researchers have long eyed the potential for lithium metal batteries, but haven't been able to overcome negative effects of the material reacting to the battery's electrolyte.

Hu offered several contributions to the field. By using an ultra thin foil, he was able reduce the size of the battery itself. He was also able to create a non-flammable and non-volatile battery that can safely operate at higher temperatures.

Normally, lithium metal batteries would only work at above 80C, which Hu notes would have been a deal-breaker. He overcame this limitation by coating the foil in a thin, solid electrolyte that doesn't require heating to function. Another contribution was a non-flammable liquid electrolyte and a mechanism to stop that from reacting with the lithium metal in an undesirable fashion.

"Combining the solid coating and new high-efficiency ionic liquid materials was the basis for SolidEnergy on the technology side," Hu said.

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