Powering the abyss: Lithium batteries drive the future of deep-sea

As the race to explore the world's oceans intensifies, scientists are turning to powerful new battery technologies to overcome one of deep-sea exploration's greatest challenges: how to keep underwater vehicles running in the planet's most extreme environment

Published in International Journal of Extreme Manufacturing, Prof. Keyu Xie from Northwestern Polytechnical universityand his coworkers from the Wuhan Institute of Marine Electric Propulsion and the China Ship Scientific Research Center thoroughly reviewed the manufacturing of deep-sea batteries, emphasizing deep-sea lithium batteries as the key to unlocking longer and more capable deep-sea missions.

Going Where Cables Can't

Most deep-sea vehicles are either tethered to the surface by power cables or rely on short-lived batteries. But cable-powered submersibles are restricted in their movement, and older battery technologies are often bulky, inefficient, or unsafe under pressure.

That's where lithium batteries come in. Known for their high energy capacity and relatively compact size, these batteries have already proven their worth in consumer electronics and electric vehicles. Now, scientists are working to adapt them to the harsh conditions of the ocean floor.

"Deep-sea batteries must be incredibly robust," says Prof. Cong Ye, one of the study's co-authors. "They need to handle intense pressure, temperature swings, and saltwater corrosion — all while providing reliable power over long periods."

Built for the Abyss

The team's review outlines how battery design and fabrication must change to meet deep-sea demands. That includes advanced materials that won't deform or degrade under pressure, smart battery management systems that can shut down faulty cells in real time, and rigorous testing protocols to ensure reliability at depths of several thousand metres.

Importantly, they argue for flexible, modular battery systems that can be tailored to specific missions. They also see potential in emerging technologies like 3D-printed battery components and underwater docking stations, which could one day allow submersibles to recharge without surfacing.

One of the main goals is to extend how long autonomous vehicles can stay underwater — a key requirement for scientific research, deep-sea mining, and environmental monitoring.

Still Some Way to Go

Despite the promise, there are still big challenges. Current batteries can't yet match the energy demands of long-duration missions, and there's no existing infrastructure for charging vehicles beneath the waves. Extreme ocean conditions continue to push battery designs to their limits.

But with the global ocean economy projected to grow significantly in coming decades — and deep-sea exploration seen as crucial to understanding climate change, biodiversity, and Earth's geology — the race is on to make these technologies viable.

"Even with today's advances, deep-sea batteries are still being pushed beyond their design limits," says Prof. Ye. "But each breakthrough brings us closer to exploring more of our oceans — and doing it safely and sustainably."

International Journal of Extreme Manufacturing (IJEM, IF: 21.3) is dedicated to publishing the best advanced manufacturing research with extreme dimensions to address both the fundamental scientific challenges and significant engineering needs.

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