By Elan Head

An award-winning journalist, Elan is also a commercial helicopter pilot and an FAA Gold Seal flight instructor with helicopter and instrument ratings. Follow her on Twitter @elanhead


Oxis Energy, battery supplier for Bye eFlyer 800, faces bankruptcy

Oxis Energy, a U.K.-based developer of lithium-sulfur (Li-S) batteries for applications including electric aircraft, has entered into administration and is selling off its patents.

Bye eFlyer 800 - Oxis batteries
Oxis Energy is a key supplier for the Bye Aerospace eFlyer 800, revealed last month. The eight-seat electric airplane is targeting a maximum range of 500 nautical miles (925 km). Bye Aerospace Image

The company confirms on its website that authorized insolvency practitioners Simon Girling and Christopher Marsden, both of the accountancy and business advisory firm BDO LLP, were appointed joint administrators of Oxis on May 19.

In a press release provided to, BDO confirmed that the majority of Oxis Energy’s 60 employees based in Oxfordshire and South Wales have been made redundant, as was first reported by the electric mobility website

“The company was unable to secure the investment required to continue its product development,” Girling stated in the release. “However, we are hopeful of obtaining a sale of the company’s specialist testing equipment, together with approximately 200 patents held by the company, and the opportunity remains for an acquirer to purchase these assets in situ at an internationally acclaimed testing center, and separate R&D facility.”

Oxis Energy’s 43 patent families cover quasi-solid state battery technology, electrolyte systems for Li-S cells, methods of Li-S cell construction, and positive and negative electrodes. Interested parties should should contact Doug Cecil at BDO by May 28, 2021.

Last month, Oxis was announced as the battery supplier for Bye Aerospace’s planned eight-seat electric airplane, the eFlyer 800. Forbes reported that Bye’s plans for the eFlyer assume a battery energy density at the cell level of 550 Watt-hours per kilogram, which Oxis expected to achieve by 2023.

Oxis reported last year that it had tested Li-S cell prototypes at 471 Wh/kg. Just last month, the company said it was “set to make solid-state lithium-sulfur cell technology a reality,” and would be deploying its Li-S cell and battery systems to clients and partners worldwide by late autumn 2021. In addition to airplanes like Bye’s eFlyers, Oxis saw potential applications for its Li-S technology in eVTOL aircraft.

In an email to, Bye Aerospace CEO George E. Bye stated, “Bye Aerospace’s eFlyer 800 program remains on track. We continue to support Oxis Energy, their lithium-sulfur cell technology, leadership, team and owners. These types of transitions occur in every industry.”

This story has been updated with additional information from a BDO press release.

Join the Conversation


  1. It’s troubling to see companies on the leading edge of technology not finding investors. Oxis was always quiet about their progress and we can’t know exactly what happened to frighten investors. However, this scenario has already happened in the past, a decade ago, when investors shied away from those electric cars. Had they not, the automotive landscape would have been very different today.

    I always tied investing with an educated vision of the future, but this lack of funding and enthusiasm is only slowing down everything. Eventually, we will find ourselves in the mess we were in with a handful of giant corporations dominating industries. Investors need to learn more about the technology, its potential applications, and the human factor. I must have an over-simplified view of the world.

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