You asked, he answered!
Lithium-ion battery inventor John B. Goodenough has responded to questions submitted by Slashdot readers. Read on for his answers.
Ready for mass production?
There are several innovative ideas for better batteries that never make it to market. The problem is that you can make a few by hand in the lab, but production of useful numbers does not scale well at all or it scales, but is horribly expensive. Will your development reasonably scale? If not, what stands in your way.
JBG: At the present time, we do not envision any problems with scale up. Although we have demonstrated with coin cells and a jelly-roll cell how to make novel cathodes, we have not optimized the cathode capacity, voltage, and discharge/charge rates. The anode problem is solved, but battery manufacturers will need to work with Li or Na anodes, which means dry-room assembly.
Critics
How do you respond to critics of the new battery technology? When can we expect to see them hit the street?
JBG: We respond by demonstrating the concepts in individual coin cells. We do not do the development work. We believe that practical batteries can be marketed in about 3 years.
Electrode material?
There seems to be some confusion about whether or not your battery has the same material or differing material on the two electrodes. Can you elaborate on this and, if the electrodes are the same material, how the battery works?
JBG: We have made zero-voltage symmetric cells Li/Li+-glass/Li that are still cycling after more than 2000 cycles at 3 mA/cm2. The key to the concept of a battery voltage that takes metallic lithium from the anode and plates it on the cathode is that a thin lithium (order of a micron thick) current collector is plated on a copper (or other) cathode lithium having a chemical potential over 3.5 V below that of metallic.
Li-ion battery fires
Could you speculate on the reasons behind the increasing frequency of Li-ion battery fires? Cheaper parts, smaller tolerances, higher energy density, or all of the above?
JBG: The origin of the Li-ion battery fires is the flammable organic-liquid electrolyte and the graphite anode. If the battery is charged too rapidly, metallic lithium is plated on the graphite, and lithium does not wet or is not wet by the electrolyte. As a result, on repeated charging, lithium dendrites (whiskers) form and grow across the liquid electrolyte to the cathode and create a short-circuit, which heats the battery and ignites the electrolyte. If the battery manufacturer does not incorporate a control of the rate of charge, fires follow.
Energy density
Over time battery energy density has improved by approximately 5-10% a year. Do you expect this trend to continue? If not, what do you expect will happen in the long-term? Are there other metrics by which you expect batteries to continue to improve?
JBG: Energy density needs to be coupled to the charge/discharge cycle life; with the organic-liquid electrolytes now in use, batteries of high volumetric and/or specific energy density undergo a poor cycle life. The ability to plate a metallic-lithium anode dendrite-free from a solid electrolyte that is not reduced on contact with metallic lithium solves the safety problem, allows a long cycle life, and maximizes the energy density for a given cathode. However, the cathode strategies to optimize the density of stored energy in a full cell are yet to be determined for three different types of cathodes.
Time to market
Assuming your new battery tech scales easily and economically for mass production and given the intensifying demand for such tech, when would you expect to see it supplant lithium-ion as the battery technology of choice for manufacturers?
JBG: It will take competent battery manufacturers about two to three years to develop a marketable product. Once the technology is demonstrated by one, others will fall into line very rapidly.
Why?
Why is every technology breakthrough I read about "five to ten years away from commercial viability?"
JBG: There is a large difference between a laboratory experiment and a workable battery product. The potential market is huge, but incremental steps will not get us there. But without a demonstration of a novel approach, the estimate of 10 years away is an expression of hope for a true breakthrough. I believe that in two to three years our novel batteries will be marketed.
Will there always be a demand for lithium?
Will there always be a demand for lithium? Demand for lithium is soaring and supply is scrabbling to keep up. If I was contemplating constructing a lithium mine/extraction facility, I would be worried that my investment might do fine for five years and then suddenly become worthless when some new battery chemistry came along. Is this fear justifiable? Is it reducing current or near-future lithium supply?
JBG: The lithium battery will give 0.3 V higher discharge voltage than sodium, and sodium cathodes are less easy to design than lithium cathodes. However, we have demonstrated good sodium batteries; and people are working on recycling of lithium, which may reduce our vulnerability to finite lithium reserves. Lithium batteries will be marketed for a long time, but sodium batteries can be expected to enter the market within 5 years.
Where to next?
I am an electrical engineer and developing a battery pack for a light electric aircraft. What do you think is the next big application for batteries after EVs and home energy storage? Into what specific area of batteries should engineers focus their work on when developing battery systems? What is your ultimate vision for battery technology? Could you elaborate?
JBG: Inexpensive batteries that are safe, have a long cycle life, a higher energy density, and a satisfactory charge/discharge rate can be expected to be on the market in about 2 to 3 years. They will have multiple applications, small and large.
Limit of energy density
John, is it (theoretically) possible for a battery to reach the same energy density as fossil fuel? Gasoline has an energy density of 46MJ/kg while a lithium based battery has an energy density of around 1MJ/kg. This would mean that an electric car, boat or airplane would have the same potential range as their oil powered brethren.
JBG: Fossil fuels will always have a higher density of stored energy, but the efficiency of electric-power storage in a battery is greater than the efficiency of a combustion engine. I believe that electric power stored in electrochemical cells can compete relatively soon in convenience and performance with the internal combustion engine without the hidden losses to society by the burning of fossil fuel.
Why aren't 12 V lithium car batteries more popular?
I've noticed that replacement lithium polymer battery packs for hybrid cars often sell for less than $1,000 on eBay, while much smaller lithium based 12 V batteries for conventional cars (with starter motors) often sell for more. As an example, here is a battery suitable for starting a small V8 that sells for $1,600.00. I would assume that it would be much easier to manufacture conventional 12 V starter batteries in volume due to the ability to put them in many more different models of vehicles. The ability to shave off 30+ pounds of weight from race cars would be enormous, so the demand is there, but why not the supply?
JBG: The lead-acid battery is here and is safe. The present Li-ion battery has safety problems and is too expensive. We need a step improvement from the lithium-ion battery to a safe metallic-lithium battery that is cheap to manufacture and to recycle. We believe we have demonstrated this is possible.
What were the problems along the way?
I'm curious about the development path leading to the recent announcement. What changed to make this battery possible now, versus a decade ago? Was it analytical techniques (better math, faster computers)? Measurement and observation tools (fast/fine X-Ray, femto-second pulsed lasers)? Overall progress in the physical, chemical and electro-chemical sciences? Assembling the right team and lab? Or was it more about waiting for a spark of insight or inspiration? Which factors dominated the development path? And what about the path forward to commercialization?
JBG: What has changed is the ability to plate dendrite-free lithium from a non-flammable solid electrolyte that has a cation conductivity nearly as high as that of the flammable liquid electrolyte of the lithium-ion battery.
Patents
1) Is there any reason these batteries cannot be used for grid-scale energy storage? 2) Who own the patents to the battery technology and will they license it cheaply or hold back the market for 20 years like the overly greedy venture capitalists behind Aquion Energy?
JBG: 1) Our technology can provide competitive grid energy storage and 2) we plan to license the technology to many manufacturers; we want to avoid an exclusive license.
What are the downsides to your sodium batteries
I am very excited about sodium batteries. As sodium is a much more environmentally friendly element to produce at large scale (my conjecture, I didn't look it up). What were the roadblocks of using sodium in previous batteries? I suspect whisker growth, but am not familiar with batteries enough to know other possibilities. With the glass version, what are the big drawbacks to using sodium instead of lithium (if any)? Thank you for your kind reply in advance!
JBG: Sodium is cheaper than lithium and widely available from the ocean. The principal drawbacks include a loss of 0.3 volts relative to lithium, fewer number of cathode materials that can serve as traditional insertion compounds, and a somewhat greater difficulty to handle in a manufacturing process. However, we have demonstrated a new battery strategy that promises to allow sodium batteries to enter the market competitively.
It's the economics
Prof. Goodenough, right now, electric cars are only for the well-to-do. In my rural area, not only do people have to drive long miles, but many of them couldn't afford a new car anyway, let alone an electric one. Do you envision battery prices coming down to the point where an electric vehicle can compete with a gas-powered car at the low end of the income scale as well as at the high end?
JBG: Yes, I do envision that within 5 years electric cars that can compete in price and performance with those powered by gasoline will become available.
What do you watch?
What other developments in the field of energy storage do you keep a close eye on? Do you foresee breakthroughs coming from other technologies such as gyroscopes or even organic hydrogen production?
JBG:I have no crystal ball on other technologies, but I would not bet on the room-temperature fuel cell powered by hydrogen gas.
Viability
We keep hearing about breakthroughs in the battery technology world to the tune of several per year. After many years in this forum, the empirical observation is that such breakthroughs are forgotten after a few months, quietly buried, practically never having a measurable impact on our lives. Please explain why your latest claim about a battery breakthrough is not going to end up following that route.
JBG:We have done many tests with laboratory cells. Manufacturing a marketable battery cell will take about 2 years of development by a competent battery company, but we have over 50 companies showing interest to be able to perform tests of our results. I am optimistic that our tests will be verified and that product development will begin soon.
How do you feel about UT patent management?
Somewhere around the mid- to late 2000s, I was researching LiFePO4 patents, and came across the University of Texas (UT) patent for which you are listed as an inventor. When I investigated licensing the patent, it was so expensive that it was not profitable to bother with the license at all. The factory partner I worked with was in China, and they were mass-producing the same LiFePO4 for jurisdictions not impacted by the patent. As I understand it, the law firm that UT chose to manage the patent set a price that was incredibly high. Then, invariably, some company would build a market for a LiFePO4 product that violated the patent, and then the law firm would step in after the company had actually done some business and sue them for all they were worth. I have to admit that this last bit was told to me by some battery industry veterans, but it seems plausible based on how the battery industry works. Nonetheless, the decision of UT to exclusively grant permission to the law firm to manage the patent kept the invention out of the market and likely cost UT some incredible amount (billions?) in royalties. How do you feel about your invention, which clearly made mass-production of the chemistry viable, being effectively kept off the market for so long? (BTW, when UT lowered their prices with, like, 5 years or so left on the patent, the factory I worked with immediately purchased the licensed material for selling their batteries in the U.S.)
JBG:UT has now developed an Office of Technology Commercialization that is much more competent. We are building a patent portfolio that I hope will prove successful, and we will not offer an exclusive license. I cannot comment on pirating by the Chinese, but I believe they are learning it is better to play by the international rules. However, where billions of dollars are at stake, the vultures are circling.
Why are they not especially robust?
Rechargeable lithium cells are clearly excellent and power the majority of battery powered things I own. However, by comparison to older, less energy dense techs, they don't seem especially robust, for instance they degrade fast if deep discharged or left at very low charge levels. By comparison, say, NiCd batteries are very robust: while they do lose life, they do it in a pretty slowly and predictable way, you don't get it going off a cliff edge. I've noticed with some (though not all) devices, the battery life drops from hours to minutes in a relatively short timespan. The battery meter also ceases working, which I assume means that the internal resistance spikes way up suddenly and at higher voltages than fresh cells. Can you offer any good insight as to why this happens, and do you think there are going to developments in the pipeline which will introduce the tolerance of the cells? Or are we going to have to rely on better quality active protection circuitry instead?
JBG:The present lithium-ion batteries have many drawbacks because they use a flammable liquid electrolyte that has a small window for a stable voltage range. We have a nonflammable solid electrolyte with a comparable cation conductivity and a large energy window to allow plating a lithium anode dendrite free; a lithium anode is still cycling after more than 2000 charge/discharge cycles and it is not oxidized by the cathode up to a 5 V discharge.
A lithium powered energy economy
Mr. Goodenough, it seems that the world's reserves of lithium are far more centralized than nearly any other energy source. Do you foresee a way to avoid the geopolitical struggles for lithium ore that we experience with oil reserves? Do you see an upper limit on the ability to recycle and reuse existing lithium batteries (those that have avoided a landfill)?
JBG:You raise an important point. We have demonstrated we can make sodium cells with only a loss of 0.3 V compared to lithium cells, and sodium is available from the oceans. However, it is important to develop the means to recycle the lithium batteries to reduce vulnerability to the situation you cite.
Too many ways to skin the cat
With so many different research approaches to improving batteries, investment in bringing new technology to production scale is often viewed as a hazardous endeavor... there's a pretty good chance the tech you pick will end up getting surpassed by another before financials break even. Obviously the free market helps foster a spirit of competition, but its brutal darwinism also serves as a disincentive. Planned market solutions can spread out risk, but also have to be wary of funding completely unworthy endeavors... if everyone working on batteries, win or lose, got a small but guaranteed "compensation prize," lots of people would jump in and claim without merit to be working on batteries. Subdividing the technology so that different phases of a manufacturing process are developed by different entities seems a promising idea for those parts of the technology that may have wider applications or may apply to multiple competing designs -- but that would require a lot of advocacy which just does not seem to be there. Have you seen any interesting proposals for business/market/public-funding models to address the "too many ways to skin a cat" problem?
JBG:True, the large prize has stimulated a world-wide competition for a solution. We have introduced the first all-solid-state technology that can operate below room temperature, is inexpensive for up to a 3-volt discharge, and can use a conventional cathode to over 4.2 V discharge with a long cycle life. Over 50 battery companies have shown interest in validating our findings and marketing products.
Battery structure and capacity
How thick is the initial anode foil of Li or Na? This determines the capacity of the battery. All quantities in the paper are expressed per gram of lithium. The cathode has particles of glass electrolyte, carbon, and sulphur, with a copper collector. When the lithium is plated onto the cathode, upon which of these components is it plated, and how thick is the plating?
JBG:You are correct to imply that plating on the cathode from the anode can only give a voltage for a finite thickness of the plated material on the cathode side. We have not yet obtained a good measure of the thickness of the cathode plating that is viable, but it appears to be micro not nanometers thick. Optimizing the capacity will involve the ability to optimize the surface area of the cathode material. This optimization has yet to be performed, but we can plate sodium as well as lithium.
Cathode problem?
In the IEEE article, it was stated that the cathode problem has not yet been solved. Can you elaborate on this? Were the lab experiments conducted without a cathode?
JBG:We have demonstrated two approaches to the cathode of a rechargeable battery: plating of the alkali-metal anode onto a cathode current collector of lower chemical potential to a limited thickness over a large surface area and a conventional high-voltage insertion compound with a plasticizer contacting the cathode. Both work.
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