ARGONNE, Ill. When it comes to the search for alternative energy, don't forget about how to store it.
Batteries are an instrumental aspect of everyday technology, from phones to computers to cars, and an important element of the renewable energy equation.
Right now, lithium-ion batteries are the commercially dominant energy storage technology. They're good, but not perfect.
So what's next? CBSNews.com traveled to Argonne National Laboratory's research facility outside of Chicago to ask the experts.
"It's a really tough question to answer," said Michael Thackeray, a distinguished fellow and senior scientist at Argonne.} }
"The periodic table has a certain number of elements, and you want to go light, and you want to get as much electrochemical potential out of these batteries, so the choice that you have in terms of the known elements is actually very, very small."
For the immediate future, Argonne's experts say, lithium-ion technology has room to improve.
"There's an enormous amount of important research being done on lithium-ion," said Jeffrey Chamberlain, the deputy director of development and demonstration for the Joint Center for Energy Storage Research, based at Argonne.
"There's an expectation that lithium-ion could be two to three times better than it is today."
And after lithium-ion?
"A totally new way of storing energy," said Christopher Johnson, a chemist at the lab focused on the development of new battery materials, "via using air, using liquids or some sort of combination of the two."
"We're talking about very light-weight batteries and probably designs like we haven't seen yet today," added Chamberlain.
"What is cutting edge in batteries? The thing that occurs to me is the idea of storing energy in liquids."
With a few notable exceptions, much of the battery research in the past 200 years has been focused on solid-state chemistry and physics, said Chamberlain. Exploring liquid-based batteries, Chamberlain believes, would open the doors to engineering an entirely new battery device, uninhibited by the manufacturing limitations - and costs - presented by solid-state batteries.
Johnson broke down the concept: "You would be able to store the charge in a liquid that you could pump through the battery and then once it's pumped through, you could recharge it by pumping it in the opposite direction."
Another future possibility is lithium-air technology, in which oxygen from the air reacts electrochemically with the lithium. Battery researchers say lithium-air batteries have the potential to store up to five to 10 times the energy of a lithium-ion battery and the potential to be several times lighter.
"You could use oxygen as one of the carriers for charged storage," Johnson explained. "You create a product reacting in the battery with air to make a solid product like lithium peroxide or some other lithium oxide-based phase. And then you charge it up and release the oxygen out."
While it works in theory, Argonne's researchers have their doubts and acknowledge that it could be a couple of decades before lithium-air batteries are a commercial reality.
"There's a huge number of obstacles that stand in our way," said Thackeray. "Electrolyte stability, the reversibility of a metallic lithium electrode, which is one of the real bug-bears today of lithium systems. And you've got to be able to put the lithium into a container of sorts, which is another structure to reduce its reactivity."
There may be stepping stones to getting there, such as a hybrid battery in which air reacts with a liquid.
"You're using the best of both," said Johnson. "You're storing the charge on the liquid molecules, but it's reacting also with oxygen at the same time."
There are other approaches that could serve as a the basis for the next big break in battery technology, such as magnesium-based batteries or lithium-sulfur batteries.
"I'm very open about it, I think everything has to be looked at," said Thackeray. "It's possible that somebody's going to come up with a really new idea."
And while Argonne's scientists are willing to point to possible future concepts, they're hesitant to make specific predictions.
Plus, even the experts can't see the future. They can, however, spot a trend.
"I can tell you with absolute certainty, absolute certainty, batteries will be smaller, faster charging, last longer and be less expensive, and even be safer," said Chamberlain.
"That's where we're headed with battery chemistry. Now which particular chemistry? I'm not going to gamble and tell you which one that may be."