We take a lot of the technology around us today for granted. Like having mini computers for phones that last us the entire day, which was unheard of not too long ago. But what if your phone lasted 3 to 4 days on a charge? Or a laptop that could be pushed to the limits for an entire day without needing to be plugged in? Or an EV that could go 500 to 600 miles, charge in minutes … and cost less than an internal combustion engine car? There’s been a lot of hype around solid state batteries for years now, but where do things stand today? And how much longer do we have to wait before seeing solid state batteries take hold in the technology we use every day?
The excitement around solid state batteries is understandable. With companies like Toyota teasing announcing a solid state battery vehicle around the time of the Olympics, the buzz continues to grow.1 The lithium-ion batteries we use today, as great as they are, have some drawbacks that solid state is trying to solve. To understand those drawbacks we need to look at the basic components of a battery. There’s a positive electrode, or cathode, which is usually something like a Nickel Cobalt Aluminum (NCA) formula. Then there’s a perforated separator to keep it isolated from the negative side, or anode, which is usually a compound of a carbon material like graphite. Finally, all of this will be filled with a liquid electrolyte that allows the free flow of ions back and forth between the anode and cathode during charging and discharging.
You can substitute many different chemical formulations for the cathode and anode, but the liquid or gel electrolytes in most of the batteries we use today are highly combustible.2 This can happen because of manufacturing defects or damage to the cell, but it’s also a problem because of something called dendrites. Metal can build up on the anode and slowly create stalactite-like growths, and those can extend and puncture the separator between the anode and cathode … and that’s when you get exploding batteries.3
Some of the latest breakthroughs we’re seeing in research
So how does a solid state battery solve that problem? They replace the liquid electrolyte with … you probably guessed it … a solid one. Most often a ceramic or glassy electrolyte.4 These solid electrolytes aren’t flammable, which means a big improvement with safety. But a bigger benefit of solid electrolytes is the ability to use other anode materials like lithium metal. which has the highest theoretical storage capacity.5 In fact lithium metal was used in some of the first lithium ion battery research in 1979.6 However, one of the reasons we haven’t used lithium metal in batteries up until this point is because they suffer from dendrite growth, which is … as I mentioned before … kind of a bad thing.
There’s been a lot of really interesting research in recent years that may have solutions to that problem. MIT researchers have developed something called mixed ionic-electronic conductors (MIEC) and electron and li-ion insulators (ELI).7 That’s a mouthful. It’s a three-dimensional honeycomb architecture with nanoscale tubes made from MIEC. The tubes are infused with lithium metal, which forms the anode. The fascinating part of this breakthrough is that the honeycomb pattern gives the lithium metal room to expand and contract during charging and discharging. Giving the battery room to breath avoids cracking. The ELI coating the tubes acts as a barrier protecting them from the solid electrolyte. All of this means having a true solid state battery without the need for any liquid or gel mixed in … and no dendrite growth.
A company called Ion Storage Systems has developed super thin ceramic electrolyte that’s about 10 micrometers thick, which is about the same thickness as today’s plastic separators used with liquid electrolytes. Each side of the ceramic electrolyte is covered in a super thin layer of aluminum oxide that helps to reduce resistance. The company’s prototype battery had a specific energy of about 300 Wh/kg, and is capable of charging in 5 – 10 minutes.8 For a point of comparison, NCA batteries today have a specific energy of around 250 Wh/kg.
IBM and Daimler announced a “breakthrough” solid state battery that used IBM’s quantum computing on a battery chemistry that uses no heavy metals, such as nickel or cobalt, and that aren’t extracted in damaging ways.9 But unlike other big “breakthrough” announcements, they provided no details that can be explained or corroborated. All we know is what they’ve told us, like that it can supposedly charge to 80% in 5 minutes, and match the energy density of state-of-the-art lithium ion batteries. This announcement has been met with a lot of skepticism due to the lack of details.10
But one announcement, which is the biggest of them all, is back to the legendary, rock-star of battery technologies, and Nobel Prize winner, John B. Goodenough. Together with his co-author, Maria Helena Braga, they announced a “glass battery.”11 At 95 years old, John Goodenough is still researching battery chemistries to replace lithium-ion batteries with something better, faster, safer, and ecologically sound. Something that would be cheaper than gas and would push humanity off the need to use fossil fuels. Both Maria Braga and John Goodenough think they’ve unlocked that potential with their discovery.
The glass battery doesn’t use cobalt, and lithium could eventually be replaced with easily accessible sodium. That means these batteries could be biodegradable at some point. And as you probably guessed from the nickname, it’s using a glass electrolyte. They can last for more than 23,000 charge and discharge cycles, which is more than a minor improvement over several thousand for a typical lithium ion cell.
There’s still some debate from battery researchers around Goodenough and Braga’s findings, but Goodenough’s credentials as one of the inventors of lithium-ion batteries add a lot of credibility to the findings.12
What this will mean for the future
Which leads me to the giant question of “when?” When will we finally see solid state batteries hit the market? We’ve heard promises of solid state battery breakthroughs for years, but have yet to see them in the wild. And that’s part of why I selected some of the examples that I did, like the IBM example. When it comes to news reports and public perception, there’s a disconnect between research and breakthroughs in the lab versus when it becomes commercialized in the marketplace. There’s often the perception that it’ll be in a product within a year or two, which is actually something IBM stated in their announcement. They partnered with Mercedes Benz R&D North America, a Japanese chemical company Central Glass, and a battery startup, Sidus, to test the battery. A direct quote from an interview with IEEE Spectrum said:
“IBM has built prototype pouch battery cells in the lab which give her group confidence that they could develop a commercial product for limited applications (e.g. portable power tools) within one to two years.”13
One to two years! That’s exciting, unless you pay attention to the specifics of “limited applications” like portable power tools. This isn’t something that’s going to be in EVs anytime soon. Sadly, some companies perpetuate this misperception on purpose to appear as though they’re relevant and competitive in the marketplace.14 At CES this year, Mecedes showed off their AVTR concept car that is made of environmentally friendly materials, and a cutting edge battery pack that’s fully recyclable. That got a lot of the headlines, but in an interview with Mercedes senior manager of battery research, Andreas Hintennach, he stated the battery technology is currently in lab testing and about 10 to 15 years away.15 I just recently had a video about CATL and their prismatic cell to pack technology that Tesla may be using soon. Well, CATL also produced a solid state battery sample, but said it wouldn’t be commercialized until after 2030.16
I don’t bring all of this up to try to squash excitement around the research and breakthroughs with solid state batteries. It’s important to keep things in context and understand that it’s incredibly difficult to go from lab to manufacturing at scale cost effectively. Remember that it was over a decade between the original lithium-ion battery research and Sony building the first commercially available version.17 And even John Goodenough thinks it’s going to be 5-10 years before solid state batteries will become commercially successful.18 Even Toyota’s planned solid state vehicle announcement around the time of the Olympics is another good indicator. Toyota’s R&D chief has said:
“We will produce a car with solid-state batteries and unveil it to you in 2020, but mass production with solid-state batteries will be a little later.”19
And by “a little later,” he means mid 2020’s at the earliest. We’re in a giant middle step of solid state research, which is trying to apply what has been learning in the lab and apply it to real world production in limited situations. John Goodenough is doing that with Hydro-Quebec. The University of Texas at Austin owns the patents to the glass battery, but is working with Hydro-Quebec to try and commercialize the technology.20
”We believe there will be a significant development work and testing required before Hydro-Québec will know whether a product can be manufactured and how such a product might perform compared to existing Li-ion battery cells.” – University of Texas, director Office for Technology Commercialization
What I found interesting is that Hydro-Quebec has been working with the University of Texas for 25 years and it developed John Goodenough’s lithium iron phosphate battery.
We’re most likely going to see solid state battery technology hit the market in small batches in very limited ways. The difficulty in manufacturing yields and costs will mean it’s most likely going to be used in small form factors like consumer electronics. Think smartphones and smart watches. As the process and chemistries get perfected, we’ll start to see it in larger scale products, and ultimately, EVs. I wouldn’t be surprised if John Goodenough’s prediction is accurate and that we’ll see the first batteries in five years or so, but we’re most likely a decade away before it starts to make significant inroads.
But once it does, it’s going to change everything … again. Everything we know and expect out of consumer electronics, health technology, and EVs will shift. We’ll be able to charge phones and cars in minutes instead of hours. But the biggest gain is something that John Goodenough spoke about himself.
“Modern society has become dependent on energy. We have to learn to eliminate our dependence on fossil fuels so we can be dependent on the energy from the sun. But you need to be able to start … and the battery is one of the ways to store electric power efficiently. You’ve got to find a way to get around the problems of the present lithium-ion battery. And I’m hoping we found a solution to that. We have a safe, all solid state cell, of high energy density, that’s very cheap to make. Just like the lithium-ion battery gave us the wireless revolution. We will now have the ability to store energy in a big enough volume at a low enough cost that it can compete with oil. I think that it will be transformational.” – John B. Goodenough21
I’m really excited to see where solid state batteries can take us in the future, but for the time being we’ll just need to be a little patient.