It’s one of those things we probably take for granted. But if they weren’t invented, all those electronic devices that we now consider an integral part of our lives will not have reached such an elevated status. We’re talking about batteries and how they have made it possible to make our gadgets portable. Of course, batteries aren’t just good for gadgets. Bigger batteries power electric vehicles as well. And for those with solar panels, batteries make it possible to store solar energy for later use.
As useful as batteries are, there’s no doubt they’ll be even more useful if their charge lasted longer. Which is why researchers have been trying to figure out how this can be done, and how it can be done practically.
According to a team of researchers from the Lawrence Berkeley National Laboratory led by Gao Liu, they have discovered what could be a solution to this perennial dilemma, particularly when it comes to lithium-sulfur batteries. As they wrote in their paper which was recently published in the journal Nano Energy, they’ve devised a way to bind sulfur with seaweed, and doing so results in a longer-lasting battery life.
Why lithium-sulfur? Because sulfur is cheap. It’s cheap because it dissolves rapidly, but it’s tolerated because of its high energy potential. Lithium-sulfur has more than double the energy capacity of lithium-ion. It’s also lighter, which means it has more practical applications, including use in aircraft and drones.
In a lithium-sulfur battery, sulfur acts as a binder. Much like what glue does, it holds the components of the battery together, and this ensures that the electrical circuit doesn’t break. When the sulfur dissolves, the battery’s capacity dissolves with it.
As they were experimenting with binders, the team was able to zero in on carrageenan, a red seaweed derivative that’s typically used as a food thickener. Similar with a synthetic polymer they tested, carrageenan was able to act like a binder. At the same time, it reacted with sulfur in such a way that it kept sulfur from dissolving as it normally did. The outcome is a battery with a longer life span.
The team tested their theory at Berkeley Lab’s Advanced Light Source, one of the brightest sources of ultraviolet and soft x-ray beams in the entire world. It was also confirmed independently by General Motors. The results were undeniable — incorporating seaweed in a lithium-sulfur battery makes it more stable and extends its lifetime.
Moving forward, the team intends to deepen their understanding about the chemical reaction that takes place inside the battery cell. As Liu said: “After this polymer binds with sulfur, what happens next? How does it react with sulfur, and is it reversible? Understanding that will allow us to be able to develop better ways to further improve the life of lithium-sulfur batteries.”