Li-S Energy (ASX: LIS) has entered into a collaboration with UK-based underwater vehicle manufacturer MSubs to test its lithium-sulfur battery cells for use in uncrewed undersea platforms.
The agreement will see Li-S Energy evaluate its pressure-tolerant cells under simulated deep-ocean operating conditions at its Geelong facility.
The company sees the program as a key step in expanding its next-generation battery technology into the defence and autonomous marine sectors.
Lithium-Sulfur Cell Tests
Li-S Energy will assess the performance of its lithium-sulfur cells in MSubs’ specialised pressure-test chamber, which will be transported from the UK to Australia for the program.
The trials will simulate the extreme pressures encountered at depths of hundreds to thousands of metres, as well as measure cell integrity and endurance across mission-profile conditions.
Lithium-sulfur cells offer significantly lower weight, inherent safety improvements, and near-neutral buoyancy compared to conventional lithium-ion and lead-acid chemistries—properties that enhance submersible vehicle design by reducing overall mass, improving balance, and enabling increased payload capacity and endurance.
Pressure-chamber testing is scheduled to begin once the equipment arrives in the first quarter of 2026, followed by multi-day mission-profile endurance evaluations later in the year, with results from both phases to be jointly reviewed to assess potential integration of Li-S batteries into MSubs platforms.
Li-S Energy believes a successful outcome would validate its technology for deep-ocean environments, and open new commercial opportunities in defence and autonomous marine markets.
Underwater Vehicle Pioneer
MSubs is internationally recognised for designing and building manned and uncrewed underwater vehicles for defence and commercial applications.
The company’s portfolio includes systems developed for the UK Ministry of Defence – such as the Project Cetus extra-large uncrewed underwater vehicle – and platforms for the US Navy and US Special Operations Command.
Li-S chief executive officer Lee Finniear said the collaboration provides a rare opportunity to test the company’s batteries “in one of the most demanding environments imaginable.”
“The near-neutral buoyancy and lightweight nature of our cells make them particularly well-suited for undersea applications, and we look forward to working with MSubs to drive adoption in this new operating domain,” he added.
MSubs engineering director Rob Shaw said Li-S cells have the potential to deliver “major performance improvements” for next-generation uncrewed underwater vehicles by offering a lightweight, energy-dense, and pressure-tolerant power source.
