Lithium-Sulfur Cell High Energy Density Milestone Achieved

Apr 4, 2024

Gelion has achieved a high energy density milestone by fabricating a 395 Wh/kg lithium-sulfur 9.5 Ah pouch cell.

Gelion has achieved a high energy density milestone by fabricating a 395 Wh/kg lithium-sulfur 9.5 Ah pouch cell (commercial cell format). This result represents a c. 60% increase in the energy density (lower weight) compared with current lithium-ion batteries (approximately 250 Wh/kg).

Further to the announcement on 19 March 2024, Gelion had produced 1.0 Ah cells using the OXIS Gen2 cell technology that achieved energy density of 245 Wh/kg. The achievement of 395 Wh/kg aligns with the independent energy density modelling projections for a larger cell format.

By re-establishing this performance, building on the OXIS Gen 2 technology and IP acquired from Johnson Matthey, Gelion has set a baseline for comparison of their upcoming Next Generation cell which targets further performance improvements upon this announced result.

On 19 March 2024 Gelion identified that testing of our Next Generation cell technology is exhibiting our expected solid-to-solid conversion (see Glossary) behavior toward enhanced stability and longevity. We will continue to update as we progress these developments in addition to the silicon-sulfur cell development in cooperation with Ionblox.

Gelion’s ambition for its next generation platform is to unlock the potential of sulfur batteries for a wide range of global applications including mass market electric vehicles (EV), electric vertical-takeoff-and-landing (eVTOL) aircraft, drones, and stationary energy storage (ESS) as high Wh/kg translates to lighter batteries and opens many advantages for these markets. Sulfur being an abundant material offers a future not limited by geographically concentrated and controlled battery metals which significantly improves battery lifecycle sustainability.

John Wood, CEO of Gelion Said:

“This result further validates Gelion’s Li-S technology plan. In 2023 we established a leading Li-S cell technology foundation following the acquisition of OXLiD and the IP acquired from OXIS and Johnson Matthey. Whilst these are still early results, we intend to build on them actively throughout 2024, unveiling and demonstrating the unique core proposition that Gelion is assembling.

We continue to build on our position within the global battery industry and focus on establishing a strong identity and market presence which is centred on the key metrics of performance, cost, and safety, ready to leverage once our technologies go-to-market.”


In May 2023, Gelion updated on the progress made using the battery technology package acquired from Johnson Matthey (containing, in addition to its own IP, the Li-S IP and know-how from OXIS Energy). Gelion has worked over the past nine months to benchmark, improve on, and define a next generation approach to Li-S battery development.

Li-S batteries are an advanced alternative to Li-ion batteries that can achieve much greater gravimetric energy densities (measured as amount of energy per battery weight). This is critical to drive down the weight in mobile applications such as EV’s, e-aviation, and drones, reducing auxiliary component cost and lessening their upfront environmental impact. They do not contain rare metals in the cathode and can be scaled to meet the demands of global electrification. The technology shows promise to be safer (lower risk of fires) than current batteries.


Gelion PLC.
John Wood, CEOMail Iconvia Alma
Amit Gupta, CFO
Thomas Maschmeyer, Founder and Principal Technology Advisor
Cavendish Capital Markets Limited
(Nominated Adviser and Broker)
Corporate Finance
Neil McDonaldPhone Icon+44 207 220 0500
Seamus Fricker
Fergus Sullivan
Leif Powis
Alma Strategic Communications
(Financial PR Adviser)
Justine JamesPhone Icon+44 20 3405 0205
Hannah Campbell
Will Ellis HancockMail


AhAmpere hours. A measure of capacity stored in the cell. The larger the number the higher the capacity.
Energy density
The ratio of energy stored per unit weight i.e. Watt-hours per kilogram. The higher the number the lighter the battery.
Pouch cellAn industry standard format of a battery which comprises a flat pouch-shaped design with a multi-layered laminate structure.
Solid-to-solid conversionA low or polysulfide-free conversion of sulfur within the cathode. Polysulfides are a liquid form of sulfur that are corrosive and reduce cycle life in traditional lithium-sulfur batteries. Solid-to-solid conversion helps mitigate the formation of the polysulfides.

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