Rechargable batteries have come a long way in the last couple decades. The lithium-ion cells that power our smartphones, tablets, and laptops nowadays are much cheaper, lighter, and more powerful than the first models. But they can still get much better, and you should expect some major improvements in the next few years.
That's the big takeaway for mobile computing from a chat I recently had with the Argonne National Laboratory's deputy director of development and demonstration, Dr. Jeff Chamberlain.
Chamberlain explained that today's lithium-ion batteries hold about twice as much energy per pound of hardware as the cells that flew out of research labs in the early 1990s. Costs have also dropped by about half, not counting for inflation on the battery-buying dollar. All told, we're getting more than six times the energy storage value for our dollar thanks to two decades of battery research at Argonne and other institutions.
But the next step forward will be even more impressive. The U.S. Energy Department laboratory and its partners in the Joint Center for Energy Storage Research alliance aim to double or triple the efficiency of lithium-ion batteries again no later than 2018. That means repeating about half the relative progress of two decades in just five years -- from a much more advanced starting point.
There's actually even more progress on tap beyond the next-generation quantum leap, but let's start with Argonne's shorter-term goals.
"This is a lot of science and engineering that's gone into making this happen in the last 20 years," Chamberlain told me, "but maybe the most important thing for your readers is that, in that 20-year span, there's been a $13 billion market that has arisen."
That's just for portable electronics, with a very small sliver going into electric vehicles so far. Every year, the global appetite for devices such as smartphones and tablets fuels $13 billion of lithium-ion battery sales.
It's not like device builders spend a lot on batteries. For example, Apple (NASDAQ:AAPL) puts $190 worth of components into each 16-gigabyte iPhone 5s handset, according to IHS iSuppli. Only $3.60 of this bill of materials, or a minuscule 1.9% of the total cost, goes into the battery.
But the volumes are so massive that the pennies spent on batteries add up to billions of dollars every year.
What's going on in modern batteries?
So how can our phone and tablet batteries get so much better, in such a short expected period? Researchers are on the verge of major improvements to lithium-ion chemistry.
"One key thing for you and your readers to understand is, the term 'lithium ion' does not represent one technology," Chamberlain said.
Alkaline batteries, or the lead acid bricks found in most cars, are well understood, and the names actually describe their chemistry very accurately. But lithium ion is an umbrella name for a wide range of chemistry setups, all related through their focus on lithium as an electron carrier, but with large differences in the anode, cathode, and electrolyte setup.
Without getting too technical, the cathode (the negative electrode) in commercial lithium-ion batteries for portable electronics is typically made of lightweight lithium combined with elements such as manganese and/or cobalt. The anode (the positive electrode) is almost always pure graphite, and the electrolyte they dip into is various lithium salts in a carbon-based solvent.
Each of these materials can be replaced to achieve specific effects. For example, silicon-carbon cathodes offer more power per weight but cost more. These cells entered commercial use in 2013. Adding nickel to the anode makes everything better -- except for dramatically higher manufacturing costs and brand-new challenges to the battery's safety and stability.
"You can design these cathode and anode materials to be high power, or high energy, or low cost, or environmentally friendly, and it's all called lithium ion," Chamberlain said.
Now that you know the basics of lithium-ion battery chemistry, let's think about the future.
"What's coming to lithium ion is a dramatic shift in the anodes," Chamberlain explained. "So instead of graphitic carbon, there's been a push in the last five years to use silicon. Because silicon can hold seven times as much lithium as graphitic carbon can."
Seven times more energy? Wow! So what's keeping this crazy improvement out of my phone today?
"The only reason that's not commercial today is, the silicon swells about 300% when you put lithium in it," according to Chamberlain. "Can we use silicon at the anode? If we can, we'll give a massive energy boost to the battery."
That means finding a way to keep the expanding silicon electrode from bursting at the seams or damaging other battery parts. Of course, the solution can't be too expensive or sacrifice all the efficiency gains. It won't be easy, but Chamberlain believes it can be done. And when that happens, your smartphone battery becomes even smaller, lighter, and cheaper -- all without sacrificing battery life.
And beyond that?
Battery researchers' long-term goals are even more ambitious. Argonne's aim to double or triple storage efficiency in five years is trumped by truly next-generation research at the Joint Center for Energy Storage Research.
"Our objective in the Batteries and Energy Storage Hub," Chamberlain said, "is to get five times the energy density of what was the original baseline in 2011. In other words, to go beyond the theoretical capabilities of lithium ion."
The research here isn't as heavily funded as the more immediate lithium-ion project. The cutting-edge researchers have to manage their funding much like investors manage their retirement portfolios. As described by Chamberlain:
You and I as taxpayers, we fund this research like a mutual fund. Two-thirds of the Argonne energy work is focused on advanced lithium ion. About one-third of it is focused on beyond lithium ion. In my view, that's an appropriate balance. It's a portfolio of research that balances lower-risk/medium-term/medium-reward batteries -- the batteries that are almost sure to come out -- in a portfolio where you balance that with higher-risk research that, should we obtain a high-powered magnesium battery, that's a big quantum leap up in efficacy and performance that would really be a game changer.
Big things are coming to a battery pack near you, sooner than you think. And in the long run, today's lithium-ion cells will become quaintly outdated museum pieces, like the buggy whip and the eight-track player.
If the progress of battery technologies bores you, I'd say you're just not paying attention.