FROM EXXON TO NECCES: UNDERSTANDING THE SCIENCE, IMPROVING THE BATTERIES
Ann Nguyen:
Hello. I'm Ann Nguyen, Senior Associate Conference Producer with Cambridge EnerTech. Welcome to this podcast for the International Battery Seminar & Exhibit, returning to Fort Lauderdale, Florida this March 21st to 24th. I have the honor and pleasure of interviewing a key figure in the history of lithium-ion batteries, Dr. M. Stanley Whittingham, Director and Distinguished Professor of Chemistry and Materials at Binghamton University. He's also one of our featured speakers during Track 1 on Battery R&D.
Hi, Stan. It's great to have you with us today.
Stanley Whittingham:
Thank you.
Ann Nguyen:
You are a director of the NorthEast Center for Chemical Energy Storage or NECCES at Binghamton University in New York State. What's your mission there and what resources do you have for supporting it?
Stanley Whittingham:
This center is a large center supported by the Department of Energy. We, in fact, have 10 sites spreading from Cambridge in England to San Diego in California. It's really a consortium of researchers. It's funded by DOE to the tune of about over $12 million over 4 years. Our goal really is to understand all the possible reactions that could occur in lithium batteries. By doing that we hope to make better lithium batteries, ones that will last longer and lower-cost ones.
Specifically our goal is what we call closing the gap. What you calculate you can store on a lithium battery is much more what is actually available today on the market. We're trying to understand the science that's restricting us from getting the full potential out of the battery. We're looking at commercial lead oxide as one example. We're also trying to put two lithium ions into various what we call intercalation cathodes. That hasn't been done before and that will also increase the energy storage by at least 50%.
We have a mixture of experimentalists, theorists and really state-of-the-art characterization folks and they're mostly in DOE national labs with all their synchrotron facilities. One of our key efforts is to use characterization tools so we can actually see what's happening in the battery as we are cycling it.
Ann Nguyen:
Can you describe the progress you've made using operando studies for your research on particular cell-level chemical reactions and energy densities and the limitations you've had to overcome?
Stanley Whittingham:
The center's been in place since about 2009 and one of our major efforts was to design electrochemical cells that gave us real results in these large synchrotron facilities. Especially in these facilities you have to have an open window so the X-rays can get through the battery itself and this has caused problems in the past. Our colleagues at Argonne developed what we can an AMPIX cell. What we're looking at is typical of the entire battery so we can see the entire system and we know the results we're getting are real.
We find what you see in an operating battery can be quite different than what you see in materials you take after a battery after it's been able to relax, say, for one or two days which is typical. We combine what we call operando techniques, that's the in situ measurements and the ones from batteries that we've pulled apart. There are a lot of studies to make X-ray diffraction, where the material is a bit amorphous, we use what's called a pair distribution function analysis and we use a number of other techniques to measure the oxidation states of all the ions in the system.
That's a key part and our colleagues at Cambridge use nuclear magnetic resonance techniques and they now develop cells so they can actually watch, for example, lithium plating out and determine what kind of lithium it is which was not possible till now.
Ann Nguyen:
In the 1970s and early '80s, you worked for the Exxon Research and Engineering Company, which commercialized the first rechargeable lithium-ion battery. How would you sum up the battery's technical evolution in the decades since and what do you anticipate most for its future development?
Stanley Whittingham:
When you look at the battery business you have to look at what we call a technology poll, demand from the user, be that a corporation or you and I. In the 1970s, there was a large gas crisis, so Exxon and several other companies decided to become energy companies and Exxon was actually interested in making electric vehicles at that stage. As they got involved in the lithium-ion batteries, they did alpha testing in simple things like LED displays for watches. LEDs use a lot of power and the batteries would run out within a month or two so we made rechargeable.
By the mid-late '70s, there was no longer any demand really for that kind of device because oil prices had dropped precipitously again. Exxon sold the technology to various companies and I think, as is well known now, the Japanese picked up the technology -- they seem to pick up a lot of American technologies -- and went on to commercialize it. Again, I think the poll there was a lot of electronic devices pre-today's iPhones and iPads and so on. There were a lot of smaller devices then in those days including calculators and so on.
What's really happened in those 40 years since then, we've got a better anode which is the carbon anode. Exxon used aluminum. The carbon anode is relatively inert, lives a long time and works well. Then we went from, what Exxon used was titanium disulfide, went to lithium cobalt oxide which gave a higher voltage and it was much better when using with a carbon anode that lost about half a volt. Since that time we've had, I don't want to really say it's incremental, but engineering improvements mostly over the years, so the storage capability of today's lithium-ion batteries are more than double than those that first came out in, let's say, in the '90s.
Everything is getting better. The materials have changed to some extent, gone from cobalt oxide to what we call NMC or MCA to replace part of the cobalt with nickel and manganese, maybe with a bit of aluminum. These give a higher capacity and they're also safer than lithium cobalt oxide. The real issue with cobalt oxide is the price of cobalt is driven by battery usage and means it's very expensive. There's a huge drive to get it out.
About 10, 15 years ago, the Goodenough group discovered the properties of what we call olivine lithium iron phosphate. It's much safer than cobalt oxide. It only stores about half the energy per unit volume. That's found application in things like buses, grid storage and in China and taxis and things but it is of no interest for, let's say, volume-restricted applications and that includes cars. It includes all your electronics that you carry around.
The real interest today is looking for a higher energy material so we can maybe put twice as much energy in a given volume so your iPhones, your cars won't have to carry so much space for the battery in there. We expect, I would say in the next five years, for the volumetric energy tendency to increase 50%. That will probably demand that we get rid of the carbon anode or most of it and replace it maybe with tin-based compounds, maybe with some silicone-based compounds. A lot of people are working on that. There are lots and lots of challenges. I think in the meantime it's going to be a continued 1-2% increase each year and at the same time, the electronics are getting better so the electronics aren't demanding as much power.
Ann Nguyen:
Thank you Stan, for your insights and your overview of the past and the future. Much appreciated.
That was M. Stanley Whittingham of Binghamton University. He will be a featured speaker during Track 1: Battery R&D at the International Battery Seminar & Exhibit this March 21st to 24th in Fort Lauderdale. To learn more from him, visit www.internationalbatteryseminar.com for registration info and enter the keycode “Podcast”.
I'm Ann Nguyen. Thanks for listening.