Session Notes:

0:00:01   Hello, everyone I would like to think he organizes for having me in this online meeting on showing
0:00:07   some part of Fallbrook. My name is Mato Knez. I'm working in San Sebastian in the north of Spain
0:00:12   and CSE Ngwenya Research Centre. And I'm going to talk about our approach to coat particles by a
0:00:17   lady for improving with himself for batteries. Why do we actually need to improve batteries? Well,
0:00:25   there's several reasons for that. Currently, we're using fossil fuels as main source of energy, and
0:00:31   we are converting this energy by combustion. And just of course, several issues were dead, and one
0:00:36   of them is the limited availability that in those sources are not renewable. At the same time, the
0:00:42   combustion of fossil fuels generates greenhouse gases, which are sooner or later going to destroy
0:00:48   our environment, which means we have to look for alternatives or in it is energy source. The
0:00:54   alternative is the use of renewable energy sources. However, those are really available at the point
0:00:59   of use. That means that remote, and we need to find ways how to more efficiently transport or store
0:01:06   and electrical energy, which is generated at those sources now, batteries are one of the possible
0:01:12   ways how to store energy and transport. And besides, most of us in our civilization, our days have
0:01:19   mobile phones, laptops and even cars which are running electrically, which means that we need tohave
0:01:25   better batteries, larger amounts off smaller and highly capacitive batteries.
0:01:32   The currently best type batteries on the market are the lithium ion batteries, which I used in most
0:01:37   of the mobile phones or laptops. It's similar, and they have some advantages. For example, of high
0:01:42   energy density. They have excellent sacking stability in the high Siri capability. However, they
0:01:49   have also limited specific capacity, and they contained in many cases on most of the cases some raw
0:01:54   materials and a couple composition. Therefore, of course, there are always alternatives. Better
0:01:59   alternatives searched for and one of the most promising types of batteries toe succeed the lithium
0:02:06   ion batteries on a so called lithium sulphur batteries.
0:02:12   What is special about sue, for in this context, the material is abundance and it's rather
0:02:17   environmentally friendly depends always in the context, of course, but the most important point is
0:02:22   this one here. It hasn't outstanding energy density with 2600 watt hours per kilogram. This is what
0:02:30   a typical lithium. So for battery cell looks like it's a schematic when you're outside, does up with
0:02:36   your metal electrodes. On the Catholic side, there is, ah, particle assembly off so four and carbon
0:02:43   and the carbon is actually needed. Another plane deals connectivity to the whole system because so
0:02:49   far by itself is non conductive. It's an in selector,
0:02:54   and this is what we already come toe the issues which lithium So for bettering approaches now that
0:02:59   minorities have, we have several problems on the one hand on the outside, the reactive metallic
0:03:07   lithium. I can interact with the electrolyte and also can grow dens rights by the solution and every
0:03:13   deposition, which at some point will grow towards the Catholic and make a short and in this way
0:03:20   destroy the whole cell. On the other side of the couple side. We have the problem off the sofa being
0:03:26   insulating, as I mentioned before, but we also have the volume change due toa dissolution off the
0:03:32   some four, and we have traveling effect off the Sioux for through the whole system, which is called
0:03:38   the shuttle effect, and this is one of the most critical effects, which hinders the implementation
0:03:43   of lithium sulphur batteries into the market. Nowadays, the shuttle effect means in principle that
0:03:50   so, for which is insoluble, is converted with lithium, it reacts toe soluble, highly soluble with
0:03:57   your political pints. Those can travel through the electrolyte through the separated from the cattle
0:04:02   to the untold, and they'll be reduced again and travel back to the Catholic, but also form those
0:04:08   insoluble lithium selfies, which then at the end of leads to war, leakage off so four on the
0:04:15   Catholic side in the corrosion off with your money and outside
0:04:21   possible way. How to prevent this issue is the cutting off the cattle side with a lady in this way,
0:04:29   trapping the so four and prevent the leakage
0:04:35   for the batteries. The capitals are typically produced by depositing a slurry off composite
0:04:41   particles with binders and solvents on top, off aluminum foil and then drying. So, given this
0:04:48   application procedure, the possible ways to apply a RD to cattles. On the one hand, the Catholics
0:04:56   could be prefabricated end on the A R D material deposited on top off the pre assembled cattle, but
0:05:05   also on the other hand, the particles off which the slurry consists could be initially courted by L.
0:05:11   D. In some guy's bed reactor, for example, and then the whole composite material for the process
0:05:19   towards a slurry. And then I'm blade coated on top off the electrodes.
0:05:26   We wanted to compare those two factionalization methodologies before we started in the first case
0:05:31   with a pre assembled Catholic. It means we, um when you picture a Catholic consisting off. So for
0:05:39   carbon Compass site, with our content off 1.8 milligram per square centimeter off so far and then
0:05:48   you some binder and beauty after in orderto deposit the slurry on top off the electoral and then
0:05:56   subsequently did a recording off here may and bottom
0:06:02   these prefabricated Catholics being solid sheets number, then very easily coated by a lady and
0:06:09   conventional lt chambers. That means Beckham chambers and be useful processes. Process temperatures
0:06:17   off 60 75 80 85 degrees C. And for each one of those we applied low cycle numbers. That means to 5
0:06:26   10 and 20 the maximum
0:06:30   so for his arm im acted material in dilithium. So for battery, which means that it's important toe
0:06:36   have s highest possible amount of some foreign, the Catholic. And of course, this means for the
0:06:42   preparation procedure for the publication that we lose as little as possible so far now, given that
0:06:49   we have the possibility toe off the super to interact with the precursor in general. But also we
0:06:54   have different temperatures in different numbers of cycles. We had to first of all, figure out
0:07:01   whether and how much so far we actually lose your in the Ailey process. And we indeed see a tendency
0:07:07   here that the temperatures play a role. The higher the temperature, the more so for we lose, but
0:07:13   also the larger. The number of cycles is the Muslim for views and given those effects. So these were
0:07:20   done by PGM Moses we have about how much will be lost. We decided that people for the I know I've
0:07:28   only the samples up to 10 daily cycles because 20 Ailey cycles let toe significant losses so far
0:07:35   already here. That means those samples are not relevant for a listen super battery anymore. The ECM
0:07:43   analysis showed basically similar images for all the samples which have that means the standard
0:07:48   electoral, which is doctor bladed so far covering compass, ICT and then 25 and 10 daily cycles at
0:07:54   various temperatures. So we have basically in this Ailey processing no degradation off the material
0:08:02   itself. The Catholic remains please morphological e the same as it was before the e d. Expecting off
0:08:10   aluminum. In this case, aluminum is green, um, shows on the expected image. It means with the
0:08:17   increasing number of cycles we have intensity, angry, increase off the green coloration. The sample,
0:08:24   which is in line with the expectation that means the number of cycles defines the amount off
0:08:29   aluminum or aluminum which we deposited. The electrochemical analysis, however, place a more
0:08:35   important role. Ghenda morphological analysis because we're dealing with batteries and we want to
0:08:40   improve them. So from all of our capitals which we fabricated meaning to five and 10 daily cycles at
0:08:48   each for different temperatures and also distended coupled, we've fabricated coin cells and then
0:08:57   analyzed that discharge rates by means off so called see rates and the result off all these and
0:09:04   others. This even though that to A and E and five daily cycles look pretty much similar. Among the
0:09:09   samples, we have the best improvement. I'm against the standard electrode in the case, off to a lady
0:09:16   cycles at 85 degrees C. What is this? This black dotted line here. So this was our champion among
0:09:24   all of the other intellectuals. The same applies also for the second ability. So we took a look at
0:09:31   the specific capacity in the case, off to a lady cycles and five daily cycles. They look pretty much
0:09:37   similar, however, with two Ailey cycles when we have a slightly higher specific capacity, which
0:09:42   keeps constant over more than 50 cycles and a little bit less in the case of five yearly cycles.
0:09:48   Which means that even though they are similar, um, again our champion here is the oily cycles
0:09:54   fabricated 85 degrees C. So this is the black dotted line here.
0:09:59   So our approach toe coat cathodes prefabricated couples by a lady resulted in an improvement. Means
0:10:07   eliminated position with only a few cycles on the cathode can improve the battery performance
0:10:13   specific capacity, and the reason can be to force, on one hand the cohesion of particles. That means
0:10:20   we have our particles, which are interlinked and bound or glued by Elmina by L. D. Which on the one
0:10:27   hand, can, um, maintain the physical contact between the particles and therefore increase the
0:10:33   electric conductivity, but also generate or keep poor's ferocity with a functional S service off the
0:10:42   carbons, which then will benefit the electorate absorption in the capital material. On the other
0:10:48   hand, we can, by means of a only bind the police all fights which will then reduce the transport in
0:10:55   this way suppressed the shuttle effect. Onda also minimize the dissolution off the so far into the
0:11:04   electrolyte. The details of this world can be found in this publication which we published just
0:11:11   earlier this year.
0:11:14   The previously described work waas probably not too astonishing as we were expecting an improvement
0:11:20   off the battery performance if you use a l. D, especially if you use few cycles because similar work
0:11:27   has been done already before. But for us, it was more off a learning process in order to understand
0:11:33   what benefit ale can do to batteries and how to handle it Now, in the next couple of slights I will
0:11:40   describe are initially planned approach, which means we're are thinking off the particles off the
0:11:48   powders composite powerless for the batteries. We wanted to do a lady coating on top of those
0:11:54   particles before assembling the electrodes, which means for that purpose, we had to construct a
0:11:59   fluid eyes bad reactor. And then we did this some in collaboration or with help from our colleagues
0:12:05   from the DEA, Delft in the Netherlands from road phenomena. And here we used the conventional
0:12:14   composite powders in a food as bad reacted didn t m able to process all women on deposition and then
0:12:21   made the slurry out off those palace which were pre coated by L D um, and fabricated the thoughts
0:12:30   with them. Now, the good thing about this is one specific point. If you look here, we have two
0:12:37   different concentrations off so far which we can apply in the food as bed reactor. What 0.8
0:12:46   milligram per square centimetre is one of the standard mixtures off carbon with so far. So this is
0:12:51   the amount of some form. And if you increase this, um, sue for load in most of the cases, if you
0:13:00   create a slurry and then make the Catholic, it will end up in cracks. So 1.88 is the safe side, or
0:13:10   for making the capitals on the other hand, if you use those composite powders you can already hear
0:13:17   increase, um, the so four load and an increased so follow social lead toe a higher capacity and then
0:13:25   try to make the slurry Andi fabricate the coupled. And this waas one of our approaches which wanted
0:13:31   to investigate. We wanted to see whether we can use the fluid as bed reactor at the Ailey process in
0:13:37   order to increase the so four load for the powder. And in this case on this way, increase the
0:13:44   capacity off key battery.
0:13:49   The process was performed in the home built from guys bed reactor. We run it at 90 degrees C and we
0:13:55   applied similar to before 25 10 and 20 cycle numbers early second numbers. In order to call the
0:14:01   particles, of course, we do not expect to have a complete coating the particles by alien. This is
0:14:07   also not desired because aluminum is an insulator and we want oh, have a conductive material here.
0:14:13   But the binding itself this is one of the key, So the substrate for super couple composite particles
0:14:19   as conventionally used in lithium sulfur battery research and because it's of course TME and water
0:14:26   as a standard because or a Lee from icy PMS. We could see that from the change off the content off
0:14:36   aluminum is in line with the expectations. That means with the increasing number of cycles, we
0:14:41   haven't increased among off aluminum in our complicit.
0:14:48   We did some TM imaging and ADX mapping off some particles which we called it. And what we can see
0:14:55   here is the green parts. We have aluminum and oxygen, so this is significant for a woman of oxide.
0:15:03   We haven't increased signal off aluminum and oxygen, which indicates higher load with the number of
0:15:14   cycles. So the aluminum oxide is there even though it's not interconnected. That means we've rather
0:15:21   large aggregate or particles instead of a complete coating. And this is, of course, what we actually
0:15:25   want tohave. On the other hand, we have also sue for and carbon nothing that means are particles or
0:15:31   composite particles are still there. We have a significant amount off before you present, so it did
0:15:38   not finish in. This is off. Great importance for our aim, namely toe have, um, s highest possible.
0:15:46   So for loading our composite material for a better performance
0:15:53   refund by a dynamic light scattering that the particles which we process in offload as bad reactor
0:15:59   on aggregate. It means the more ale de cycles we apply, the larger is the average particle sized.
0:16:07   That means theologian, um, oxide excess glue and got in this case, and the particles are at the end
0:16:14   with 20 cycles well above the size which they showed originally.
0:16:21   But the sofa loss is one of the most important parameters in our compass site. We want to lose as
0:16:27   little as possible, so four and therefore analyzed all the samples which you produced by T. J. A.
0:16:33   And we figured out that low cycle members do not really result in a significant loss. But if you go
0:16:39   towards 10 and 20 ale the cycles, um, this obviously results in our evaporation or binding or
0:16:48   decomposition of the soup or and therefore to a loss in our compass ICT. I'm for us, the upper limit
0:16:58   off. So for loss, which we found acceptable waas 15% it means we omitted also in this case, like in
0:17:04   the previous case, the 20 ale de cycle processed powders because the super loss was simply too high.
0:17:12   The rest was electrochemical analyzed de ECM analysis saw the morphological characterization off, or
0:17:21   cathodes which have been used from our partners. They gave us a very, very interesting insight. So
0:17:26   know what you see here is the standard Catholic produced, with 1.8 milligram per square centimeters.
0:17:32   Hoover, which results typically incorrect information on which then eventually decreases the
0:17:41   capacity off the veteran. So this is awesome, something which is very well known, and this 1.8
0:17:49   milligrams is the upper limit that you can apply. It could go higher with a super amount. Such a
0:17:54   picture occurs. That means the interaction between the particles is weakened and also the
0:18:00   interaction between the slurry and substrate did the electoral itself the home which results in the
0:18:08   elimination and respectively, a little softy off the coupled. If you do apply a little powders, try
0:18:15   it toe slurry, a fabrication and the cathode application. We obviously increased the interaction
0:18:24   between the particles and also the direction between the particles from the slurry and the Catholic
0:18:32   about the current collector. And you see this in this case that after two and five daily cycles for
0:18:39   both cases on 50.8 milligrams, so four per square centimeter and 3.6 we don't see any cracks. That
0:18:47   means we have a homogeneous, um, situation where we don't have a least not obviously expressed a
0:18:56   cranks, which could then potentially lower the capacity or make the battery fail. If you increase
0:19:04   the cycle numbers to 10 we have, ah, currents off some cracks in the in the films here, which we
0:19:12   don't exactly yet know where they come from. So it is a little bit off a speculation, but most
0:19:18   likely here, the aluminum amount or aluminum oxide amount is too high. End changes completely the
0:19:26   waiting properties off the whole material.
0:19:31   If you take a look to the electrochemical analysis and consider the specific capacity which we
0:19:36   measure them from our batteries, which we assembled soul again, used coin cells. We see an increase
0:19:42   in the specific capacity for all ale, the processed samples compared to the standard sample, which
0:19:48   is great here, and it depends a little bit on the point of view. So two or five LD cycles are, um,
0:19:58   both very, very much improving the specific capacity. But together with the consideration off the
0:20:07   cycle ability, where on the five yearly cycle sample all performed off the others. We have toe
0:20:14   choose our champion and our champion in this case was the five Alieu cycle samples example which
0:20:22   significantly improved the standard cattle. But for the case off 1.8 milligram per square centimeter
0:20:31   if he doubled soup followed in the composite powder before a leader position. We have a very
0:20:36   interesting situation, so the discharge rates they're increasing for lo discharge currents, but
0:20:44   decreasing or high this judge currents. There's a very, very interesting development, however, on
0:20:50   the comparison here, with a standard system, is not really optimal because the standard electrodes
0:20:57   are produced with 1.8 milligram per square centimeter, which means that a direct comparison is not
0:21:03   possible at all. And the standard Catholics cannot be produced with diesel models.
0:21:12   If you then add to the comparison 1.8 milligram parts off for a centimeter. We have, ah, very nice
0:21:20   picture here, which shows us that the higher soulful load benefits the low see rates. Now that means
0:21:27   we increase the specific capacity of the system at lossy rates. While it is opposite in the highest
0:21:34   rated. That means once again to Muslim. Here is clearly better in a case off the 1.8 Millikan. So
0:21:42   for possible centimeter, if you take a look to the results, they tell us that annulment of the
0:21:49   position so a leader position point. Our Super column comp aside before assembling the cathode is
0:21:56   clearly beneficial. But the aluminum the position will result in a better cohesion off the particles
0:22:01   in this metal on the one hand, eliminate cracks and holes as we could see from our CM images. That
0:22:07   means delamination and cracking will not occurred it easily, and therefore the electronic
0:22:13   conductivity and the electrolyte impregnation into the powders into the coated cattle will be
0:22:20   improved. But also what we saw is that the sofa loaded can be increased. I understand. Did Cath
0:22:28   thought the sofa loading is limited toe? A maximum of 1.8 milligram per square centimeter, we can
0:22:35   hear go up to 3.6. That means we can double on the loading of super, which is the active material in
0:22:41   our case. And this clearly can increase the capacity of the system. I gotta hand Also, the
0:22:47   deposition can bind, the police will fight. It means the alumina canon trip. So for in some way. And
0:22:53   these were blocking the air transport. It means the shuttle effect will be diminished because young
0:22:59   women are protects and shields so far and also on the super Bill. I'm not that easily dissolve in
0:23:07   the electrolyte. It means, um, Alumina has a clearly beneficial effect here
0:23:14   as a conclusion from this part of the book is we have found on interesting alternative for the
0:23:20   fabrication off the lithium sulfur cathodes. It means if you use, um food as bed reactor, any kind
0:23:29   off part of male DeCota with only a few cycles in our case, it was finally cycles off. Alumina off
0:23:37   the sofa. Kabul copas. Before assembly of the Catholic, you will be able tow, assemble electrodes
0:23:46   which are crack free and hold free. And you can even increase the soup for loading. And this is one
0:23:53   of the most important points because so far is the active material in the hole with simple battery,
0:23:59   that means increasing the amount of before they'll also increase the deeper the performance off the
0:24:04   battery. Of course, that means at the end we haven't improved capacity, which we have shown in our
0:24:10   coin cells, which were which was fabricated. And this specifically means that great day 1.8. So the
0:24:17   standard amount off sue four in the compas ICT. We could increase the specific capacity compared to
0:24:23   the standard system by 30% at low see rates and at high sea rates, we could even improve it by 50%.
0:24:30   And for the lossy rates on increase off the soup before also increase the specific capacity it means
0:24:37   here. Compared to the standard system, we even reached 60% off improved. But this work most so
0:24:44   interesting that we applied for a patent for it.
0:24:49   Finally, I want to thank the members of my team for doing a great work on for the specific work here
0:24:56   on the palace. I want to thank Sarah Gothia. She did her PhD on his work and she did an excellent
0:25:02   job. And also Michaela, our technician who built up the food as better reactor bond, made the whole
0:25:10   thing run. But also all the others in the group who contributed in some way to the work. Then we
0:25:18   have our partners etc. The tech, who are specialists in better research. And this project was done
0:25:24   in cooperation with them. So are all the battery testing and assembly was done. Synthetic. Andi,
0:25:30   these are the people who predicted the world can see the tech. I also want to think route from woman
0:25:37   and I'm yellow from you left for helping us with the assembly off the food as bed reactor. And of
0:25:41   course, all the funding which we received from the curve as Spanish government, the bus governments
0:25:47   and I want to thank you for your patients.