Lithium-sulphur batteries represent just one of many technologies that are being developed as a possible future avenue for low-cost, high-performance batteries. In recent months, there have been a number of announcements surrounding the development of lithium- sulphur batteries from key players, including Gelion, Lyten, Zeta Energy and Li-S Energy, throwing lithium-sulphur batteries into the spotlight.

What advantages and challenges does lithium-sulphur offer?

In theory, lithium-sulphur batteries have the potential to offer energy densities up to five times greater than those of traditional lithium-ion batteries. Moreover, the reliance on abundant elements like sulphur, as opposed to rarer materials like cobalt or nickel, lithium-sulphur has the potential to be incredibly cheap.

Safety is also a key advantage, as the absence of oxygen-containing elements within the chemistry eliminates the risk of thermal runaway. Additionally, these batteries have the potential to significantly reduce overall battery weight.  

However, challenges persist, particularly regarding shorter cycle life compared to lithium-ion batteries and slower power performance.

What does the lithium-sulphur market look like?

The lithium-sulphur market remains small, with only a handful of players fully devoted to it, primarily spread across the US and Australia. However, in recent months there have been a number of developments in this space.

Gelion

A spin off from the University of Sydney, the company is focusing on creating next generation lithium-sulphur batteries for mobility solutions and stationary storage. In April 2024, the company announced it had achieved a milestone in energy density of its cells. Successfully manufacturing a 9.5Ah lithium-sulphur pouch cell with 395Wh/kg gravimetric energy density. This built on a previous announcement in March that Gelion had fabricated a 1Ah cell with a 245Wh/kg gravimetric energy density using OXIS Gen2 cell technology (IP acquired from Johnson Matthey).

As well as its lithium- sulphur technology, the company is also developing silicon-sulphur cells in collaborations with US firm Ionblox.

Lyten

US based, Lyten, in March 2024, announced an update regarding its manufacturing performance of its lithium-sulphur batteries. Using standard lithium-ion manufacturing equipment and processes the company achieved a 90% yield from its pilot production line. The company converted the lithium-ion manufacturing equipment in six weeks with minimal capital costs. This demonstrated Lyten’s ability to efficiently convert existing lithium-ion gigafactories to its lithium-sulphur technology.

The company expects to begin delivering cells to non-EV customers for applications in aerospace and defence in 2024. In the EV space, Lyten has collaborated with Chrysler (Stellantis Group), which hopes to use its lithium-sulphur cells in Chrysler’s Halcyon Concept vehicles.

Zeta Energy

In October 2023, Zeta announced it had produced multi layered pouch cells under lab conditions cells. The cells with a 300 Wh/kg gravimetric energy density ranged in size from 1-20Ah and were constructed using lithiated vertically-aligned carbon nanotube anodes and sulphurised carbon cathodes.

The company hopes to begin pilot production of pouch cells in 2024 and plans to make its cells commercially available by 2025 with an ambition to reach a gravimetric energy density of 450Wh/kg.

In April 2024, Zeta announced a partnership with Indian based battery cell technology developer start up, Log9 Materials. The pair plan to improve Zeta’s cells. The partnership also offers Zeta the opportunity to enter the growing India market.

Li-S Energy

Finally, Li-S Energy, an Australian based lithium-sulphur start up. In April 2023, the company announced it had achieved the development of its third generation, semisolid state, 20-layer, lithium-sulphur battery cell with a gravimetric density of 400Wh/kg. In January 2024, it announced the commissioning of the 3rd phase of its 2MWh production facility. The company was expecting to produce its first cells in Q1 2024 but has experienced delays. It anticipates that the GEN3 cells will attract considerable attention from key players in sectors like drones and eAviation, where it already has partnerships.

Rho’s Evaluation, what’s next for Li-S?

Lithium-sulphur is definitely a promising battery technology that has a plethora of advantages over incumbent lithium-ion technologies. However, the road to commercialisation of this technology is challenging and one that requires significant financial investment. Chemistries such as LFP or NCM are well established. This considered, as lithium-sulphur technology matures, in the short term it is likely to carve out a niche in sectors such as aviation. However, in the longer term it will likely play a key part of a diverse battery landscape.

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Image credit: Adobe Stock

Sources: Gelion, Lyten, Zeta Energy, Li-S Energy