Looking to the Sea to Carry Lithium-Ion Batteries

Few people would argue the superiority of lithium-ion batteries as compared to alkaline, lead-acid, and other types of batteries. Lithium-ion technology has proved so effective that it is the preferred technology for building the batteries that will eventually lead to viable electric vehicles. But even lithium-ion products in consumer form factors are gaining traction over disposables and other rechargeable batteries.

This is all good news, but there is a troubling reality on the horizon: lithium is hard to come by. Lithium is indeed out there and waiting to be harvested. However, obtaining is not as easy as it might sound. Thus, there are not a whole lot of companies producing it. To say lithium is in short supply is to state the obvious.

One possible solution is to pull it out of the sea. According to the American Association for the Advancement of Science (AAAS), the world’s oceans contain an estimated 100 billion tons of it. For all intents and purposes, the sea offers a virtually unlimited supply. Researchers at Stanford are now trying to find a way to efficiently harvest it.

Pulling Lithium from the Sea

The AAAS says previous attempts to harvest lithium from the sea centered around filtration. While it works both in theory and principle, obtaining enough lithium to make the process worthwhile requires evaporating most of the water. So you do an awful lot of work for a very low yield.

Researchers then turned to the idea of using electrodes to pull lithium directly out of sea water. Previous attempts at such processes didn’t work out well either. Why? Because sodium is attracted to the electrodes along with the lithium. Sodium is so abundant in sea water that It overwhelms the electrodes to the extent that you barely get any lithium.

The Stanford researchers mentioned by the AAAS have done something slightly different. First, they coated their electrodes with a titanium dioxide barrier. This barrier acts as a filter of sorts, allowing smaller lithium ions to pass through more easily than larger sodium ions.

Next, they alternated their current instead. They passed a negative charge through the electrode, shut things off briefly, then passed a positive charge through. Then they shut it off and repeated the process. After 10 cycles they obtained equal parts sodium and lithium taken from the water – a huge improvement

A Big Step for Lithium-Ion Batteries

Researchers still have a long way to go to perfect the process of harvesting lithium from sea water. But once they do, it will be a big step for lithium-ion battery manufacturing. Everything from car batteries to consumer cells should benefit.

Pale Blue Earth, makers of USB rechargeable batteries for electronic devices, says that the total volume of lithium in a typical consumer cell is about 3%. Cobalt makes up a higher volume, and accounts for much of the higher cost of lithium-ion batteries. But if the supply of lithium does not catch up with demand in the next few years, battery prices will climb even higher.

Easily obtainable lithium becomes cheap lithium. That is what Pale Blue Earth, Tesla, and so many other companies are banking on. A cheap supply of lithium would help bring battery prices down.

Perhaps researchers working on extracting lithium from seawater can come up with a companion process to remove the sodium as well. A dual solution could both increase the supply of lithium and solve some of the fresh water challenges the world now faces.

That would be something. For now, though, it is all about turning to the sea to carry lithium-ion batteries into the future.