Seawater-Based Batteries Last 4 Times Longer Than Lithium

New technology could allow these salt-based batteries, made with sodium-sulfur, to leapfrog current battery technology. Could this be the affordable, clean storage breakthrough we’ve been seeking?

Research at Australia’s University of Sydney School of Chemical and Biomolecular Engineering has made major strides in optimizing a salt-based battery. The basic core of the battery is extracted from seawater. Researcher Dr Shenlong Zhao notes that salt-based batteries have been around for many years, but until now no one has been able to achieve high levels of storage and performance.

In fact, you may remember a promising company called Aquion, based in Massachusetts. I wrote about them a few years ago. They had a promising salt-based offering, but suffered some funding setbacks. I checked the company’s website, and they appear to have abandoned salt-based technology for more mainstream (lead, lithium, etc.) battery systems. Perhaps their iteration of salt storage was not ready for prime time.

But this new Sydney technology could break that market barrier.

The difference, according to the University, “Using a simple pyrolysis process and carbon-based electrodes to improve the reactivity of sulphur and the reversibility of reactions between sulphur and sodium, the researchers’ battery has shaken off its formerly sluggish reputation, exhibiting super-high capacity and ultra-long life at room temperature.”

To put the performance of these batteries in scientific terms, this excerpt is from the original published report in Advanced Materials: “The S@MoS₂-Mo₁/SGF material exhibits an unprecedented reversible capacity of 505 mAh g⁻¹ over 1000 cycles with a low capacity fading rate of 0.05% per cycle.”

Research data demonstrates the battery performance achieved in the laboratory using various criteria.

Translation: The batteries are extremely durable and powerful. They can hold a high charge, with very little degradation over time. They also operate at room temperature, and do not require special storage or cooling.

Another perk is that the chemical content of the batteries should be relatively non-toxic to dispose of, unlike many heavy-metal based alternatives.

The University of Sydney has a dedicated lab for testing alternative storage systems. They have built prototypes of the new salt-sodium batteries, which they say are specifically oriented toward large-scale solar storage of energy. They will be working toward a commercially viable prototype in coming months.