Oxis Energy expects to start delivering its solid-state lithium-sulfur (Li-S) batteries to customers for trial applications in the fall of 2021. The UK company says the technology will offer significantly improved performance for electric aircraft developers, compared with existing lithium-ion batteries.
The first generation of Oxis’s Quasi Solid-State Li-S cells will have a specific energy of 450 Wh/kg and an energy density of 550 Wh/L. The company believes these levels could be boosted to 550 Wh/kg and 700 Wh/L by the fall of 2023, and then to 600 Wh/kg and 900 Wh/L by 2026.
Generally speaking, energy levels of around 400 Wh/kg have been regarded by some as the tipping point for making lithium-ion batteries viable for electric aircraft. Currently, levels of around 220 to 250 Wh/kg are more typical in the sector.
Oxis is looking to supply its batteries to electric aircraft manufacturers and propulsion system companies. It is already partnered with Bye Aerospace for its eFlyer family of aircraft and with engine group Safran for its electric motors.
“Based on our existing U.S. client base, we know that aircraft manufacturers welcome the move from conventional to solid-state Li-S [batteries],” said Oxis Energy CEO Huw Hampson Jones. He claimed that lithium-sulfur cells are safer than those using lithium-ion because the sulfur prevents corrosion in the lithium metal through a process of passivation.
The company is also offering the new Li-S batteries for various marine, defense, and ground vehicle applications. It has been developing the technology over the past four years and three years ago filed nine sets of patent applications.