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Michigan entrepreneur Ann Marie Sastry has left vacuum-maker Dyson, two years after it acquired her controverial lithium-ion battery company, Axios has learned. The $90 million all-cash buyout remains one of the richest lithium-ion deals ever.

Quick take: Sources with knowledge of the situation were not certain of the circumstances of Sastry's departure. But it comes eight months after Dyson relinquished Sakti3's core battery patents, and doubts remain in the field regarding her main claim, asserted repeatedly — that she was on the verge of commercializing much-sought-after solid state battery technology.

Why it matters: For the last two years, Dyson founder James Dyson has spoken of ambitious plans to spend $1 billion to $3 billion to revolutionize batteries and electric cars. He has said said his electric car will ready for the road by 2020. At the time, Dyson's October 2015 purchase of Sakti3 was the spearpoint of the mission, and Sastry's departure suggests more internal turmoil than he has let on.

  • Sastry's Linkedin page says she left Dyson last month. She identifies herself as the founder and CEO of a company called Amesite, which a source said is involved with artificial intelligence and education.

In September, Dyson told Bloomberg that he had created two competing battery teams—Sakti3, plus another that was attempting a different approach to solid state. One explanation for Sastry's departure was that the other team won. In an interview with the Guardian, Dyson said the company's batteries were already more efficient than those in commercial electric vehicles.

At the time of the October 2015 deal and since, numerous leading U.S. battery researchers told me they wondered why Dyson had bought Sakti3. Despite Sastry's robust claims of the company's progress with solid state, she had revealed very little publicly and, since no one else had made much progress, the deep suspicion was that she was exaggerating. Indeed, in reporting for a story at the time of the buyout, former Sakti3 executives told me that the doubters were correct—the company's technology was rudimentary and nowhere near commercial.

Dyson said Sastry is no longer with the company but declined to comment further. Sastry could not be reached.

Dan Primack contributed to this story.

Go deeper

Updated 2 hours ago - Politics & Policy

Omicron dashboard

Illustration: Brendan Lynch/Axios

  1. Health: Pfizer and Moderna boosters overwhelmingly prevent Omicron hospitalizations, CDC finds — Omicron pushes COVID deaths toward 2,000 per day — The pandemic-proof health care giant.
  2. Vaccines: The case for Operation Warp Speed 2.0 — Starbucks drops worker vaccine or test requirement after SCOTUS ruling — Kids' COVID vaccination rates are particularly low in rural America.
  3. Politics: Biden concedes U.S. should have done more testing — Arizona says it "will not be intimidated" by Biden on anti-mask school policies — Federal judge blocks Biden's vaccine mandate for federal workers.
  4. World: American Airlines flight to London forced to turn around over mask dispute — WHO: COVID health emergency could end this year — Greece imposes vaccine mandate for people 60 and older — Austria approves COVID vaccine mandate for adults.
  5. Variant tracker

Arizona governor sues Biden administration over COVID funds tied to mandates

A teacher prepares a hallway barrier to help students maintain social distancing at John B. Wright Elementary School in Tucson, Arizona, on Aug. 14, 2020. Photo: Cheney Orr/Bloomberg via Getty Images

Arizona Gov. Doug Ducey (R) filed a lawsuit Friday against the Biden administration for ordering the state to stop allocating federal COVID relief funds to schools that don't comply with public health recommendations such as masking, the Arizona Republic reports.

Why it matters: The Treasury Department said last week that the state would have to pay back the money if Ducey does not redesignate the $173 million programs to ensure they don't "undermine efforts to stop the spread of COVID-19."

Federal judge blocks Biden's vaccine mandate for federal workers

President Biden speaking from Eisenhower Executive Office Building on Jan. 21. Photo: Yuri Gripas/Abaca/Bloomberg via Getty Images

A federal judge in Texas blocked the Biden administration from enforcing its coronavirus vaccine mandate for federal workers on Friday, citing the outcome of last week's Supreme Court ruling that nullified the administration's vaccine-or-test requirement for large employers.

Why it matters: It's a blow to President Biden's efforts to increase the U.S.' vaccination rates, though much of the federal workforce has already been vaccinated against the virus.