Truly sustainable energy storage | 91TV
Transcript
- Thank you very much, Peter, for this introduction, and thank you all for coming. It's
- amazing to see so many friends mixed together with old colleagues, new colleagues. It's a
- bit overwhelming, but I hope I'll live to the expectations. Of course, it's late in the evening,
- so this lecture will be very light. I also have a lot of my non-scientific friends in here,
- so we'll just keep it very low-profile, and I'll even show you some pictures of when I was younger.
- So without any ado, as Peter said, that’s kind of been my career trajectory so far. So one thing
- that you can distil from this is that I moved a lot. So I was born in Romania, in Bucharest, and
- after that, straight after university I somehow - not quite sure how - I ended up at the synchrotron
- in DESY in Hamburg That was followed by a master’s at Rostock University, which is a very small city
- up north in Germany. When I moved there
- it was still early 2000s, so things were interesting to say. There were still a lot of
- reminders of East Germany. After Rostock I got a PhD position in Mainz, which is another small city
- in Germany, and then I moved to Dortmund. I'll tell you the story why.
- After that I finally moved to Berlin, which was my dream city
- where I actually always wanted to end up. but it took me a while to get there.
- Since 2013 I'm here in London. So I just want to show you a little bit more details, because this
- is a talk about myself, so maybe share with you some things about my career path which is probably
- not the most usual one, at least for a Royal Society lecture, but I'm very happy that things
- are changing and that you can be a little bit different and still get the Royal Society award.
- So I grew up in Communist Romania. That wasn't much fun, and the fact that I had
- those funny pompoms on my hair is not my fault. It was kind of compulsory. You couldn't go to
- school without them. I was a child in a very hard dictatorship. I didn't see a banana until
- I was 14, but that doesn't matter. It's not so important. Things start changing, but there was
- a sense of general confusion when we went to university, and that is actually a picture in
- the lab. That's my friend Ifana. Ifana sits there in the back behind Mary. So I guess that was at
- the end of the term when everything finished and Ifana was sitting in the fume cupboard I think,
- and we were sitting on the benches but it was all cleaned up. University was confusing, and the '90s
- in Romania were a bit confusing, so I decided to run away. The first opportunity that came I took.
- As I said, I ended up at the synchrotron in Hamburg, very confused
- and very young, and very skinny by the look of it as well. Then from there I got an offer for a
- master's at Rostock University, which is actually not in chemistry but in condensed physics. So I
- was pending between DESY and Rostock, and I was doing, strangely, research on ferroelectrics
- and the characterisation using a lot of X-ray diffractions. That wasn't really my thing, so
- I then decided to get a PhD into something that was more chemistry-like,
- and so that brought me to Mainz. That was an amazing research group, and I did have
- a lot of fun in Mainz. There in the middle… I don't think I have a pointer, or maybe I do.
- Yes. This is Klaus Unger, who was my first mentor. He wasn't my PhD supervisor officially
- as I was working with his habilitant, but he was one of the persons that inspired me quite
- a lot. He unfortunately passed away last year and I will always remember him.
- Because life is never so nice, my boss decided to actually get a real job, to become a professor,
- and he moved to the University of Dortmund. I'm sorry if there is anyone from Dortmund here, but
- I didn't quite like it very much, so I decided to get out as soon as possible. So I got my PhD and
- moved to Berlin, and the reason I moved to Berlin, you know, people think that we're always driven by
- ambitious and career, but actually I moved to Berlin because I really wanted to live
- in that city. So it was first the city and then what is good in research in Berlin. So this is
- how I ended up at the Max Planck Institute in Berlin, and I did live in Berlin 2005 to 2007.
- I did have a lot of fun. I did enjoy every bit of Berlin, including the techno parties, and people
- make fun of me because I always show this picture. This is the biggest techno club in Berlin.
- It's called Berghain. It's probably the first time someone shows this in the Royal Society.
- It's also very special for me because that's where I met my partner. So that was it. I not only had
- fun but also I worked very hard. I got my first independent position in 2007 as a group leader,
- and I start building slowly my group, and we kept growing and growing and growing. It was fantastic
- until basically my contract finished, and in Germany at the time… Things are changing, but
- at the time once you finish your habilitation you basically need to look for a job. So habilitation
- only gives you the right to become a professor, so you will need to find a professorship. Somehow
- I found Queen Mary, and I've decided to move from Berlin, from a relatively large group
- to Queen Mary, and I ended up with two PhD students from a large group and nothing,
- so I had to really build it up from scratch. Funny story is that I moved to London in 2013,
- and although Romania was in the European Union since I believe 2006
- it turned out we didn't have the right to work. Only Romanians and Bulgarians. On the application
- form they only asked me if I was a member of the European Union. I said yes, and when I arrived
- it turned out that I didn't have the right to work. So this is a secret? Well, it's not a
- secret because it's going to go on YouTube, but I was kind of working illegally for six months,
- and when I got my permit, one day after Romanians and Bulgarians had full working rights. With the
- current situation this might become handy again, so I'm keeping it. So again things start getting
- better and I start rebuilding my group from scratch, graduating some PhD students,
- winning some awards, continuing to have fun with my group, going to conferences. Ana joined Queen
- Mary, which was a fantastic moment. Ana is sitting also kind of behind Omar, and she joined as a
- research fellow at Queen Mary, and we kind of joined our forces
- and I'm very proud of her. She's doing amazing. Then we moved to Imperial, which seems like an
- easy thing, but it's not quite easy to take all this amount of people across from east
- London to west London. Luckily the department was very welcoming, and they did everything
- they could to accommodate us. It was 2019, so things were normal. So I integrated quite well,
- and then the pandemic came. As the picture of us in 2020 in Hyde Park, and just to make it
- very clear we are not breaking any rules here. So I might have worked illegal for six months,
- but this was when the UK government said it's okay for unlimited number of people to meet in parks.
- They changed it after that, but we are fully legal. So in terms of research I did all sorts
- of things. It took me a while to realise what I want to do. I started with organic chemistry in my
- bachelor and then, as I said, strangely I worked for a while on ferroelectrics.
- Then I did my PhD on molecularly imprinted polymers, which is quite an interesting topic.
- It's some sort of a synthetic antibody, so you polymerise something around a biomolecule of
- interest and then you extract the biomolecule and you kind of get, as I said, a synthetic antibody.
- So my PhD involved a lot of chromatography but I started working with porous materials and from
- there I moved into renewable energy storage and conversion, and I will tell you how I did that.
- So when I moved to Berlin as a postdoc, my job was using my chromatography background
- to convert biomass into useful chemicals like this, and then
- create some sort of molecularly imprinted polymers or some sort of a chromatographic column able to
- separate these molecules from each other. So what I started doing was hydrothermally
- treating biomass to get these chemicals, but every time I did that instead
- I was getting this black precipitate at the bottom of my reactor. So rather than doing my job
- I became very curious, and I started looking instead, what is this black precipitate that forms
- during this hydrothermal treatment? Tt turned out that you got some really nice spherical particles.
- So this was kind of my path to glory, or the first glory so to say, because I discovered a new way of
- converting biomass into carbon materials at very low temperature in water. So a bit of a soldier
- process of carbon. In fact what this process does, it mimics the natural formation of coal.
- Coal is formed in water with a bit of heat and a bit of pressure, but it takes
- nature 100 million of years or more to do that, and I was able to do that in a few hours.
- So I focussed myself onto this rather than this, and I start understanding the structure of this
- material and later when I moved to the UK looking for their application. Through this process you
- also get another phase which is in between the aqueous phase, that contains these chemicals I was
- supposed to be working on but I didn't, and I got also fascinated by this. These are the so-called
- carbon dots that are some nice, fluorescent, complicated carbonaceous materials that have
- potential to be used along in photocatalysis, maybe not as photocatalysts themselves, but
- along with semiconductors to change bandgap and things like this. So basically that's how I got
- into carbon materials. These are some structures that you make via this hydrothermal carbonisation,
- and it's a nice, versatile technique because you could change morphology, porosity,
- you could do all sorts of nanostructures. You could basically tailor the structure of any carbon
- material you want in any shape you want. So it's a very versatile technique.
- You can also hybridise it with inorganics and get this beautiful nanostructure where you have
- carbon that is made from biomass with some nanoparticles in the middle. So here are some
- platinum nanoparticles onto carbon, and you could make a carbon hollow sphere, and if you
- really want you can just put one single platinum nanoparticle in the middle of the spheres,
- and all sorts of other interesting nanostructure. These are some thin oxide
- carbon composites with mesoporosity. This is a lithium-iron phosphate coated with carbon.
- All these materials are useful for batteries and things like this. Oops. Something happened.
- There was supposed to be an NMR spectra there but it's gone. I was just trying to say that not only
- I was doing all these beautiful morphologies, but in my past life I was also doing a lot of C13 NMR
- trying to understand the structure of these materials. How do you go from biomass in water
- at 200 degrees to these spherical carbons? What they are, what the structure is formed,
- it turns out is formed of all these furanic structures, and if you would have the
- NMR spectra I could prove it but somehow it's gone. So just to summarise, this was
- kind of a big thing for me, because once I start talking about these hydrothermal carbonisation
- the world starts taking up this technology, and it's nice to see how basically from when I start
- working on this up to now endless groups have been taken up this technology and start using it
- to make carbon materials. I know that we shouldn't be talking about H indexes and citations. This is
- not my own H index. This is the H index of the technique that I discovered, and it's very nice
- to see this, but today I didn't get this award for the discovery of hydrothermal carbonisation.
- I actually got the award for the application of this type of materials in batteries and catalysis.
- So I want to talk a little bit about green bat and green cat, in case you've been wondering what that
- means. I'm just trying to make it a little bit more fun. So, of course, I don't need to tell
- to anyone in this audience how important climate change is. It's the biggest challenge we have, and
- this is basically what's going to happen if we don't do anything about it. It's predicted that
- by 2100 we're going to have a 4.8-degree increase in temperature. So we all know that that's going
- to be the end. I hope everyone has seen the movie 'Don't Look Up'. I think it was a fantastic movie
- and speaks exactly about this problem. Luckily we have a lot of policies in place.
- the Paris Agreement of course, and also some more local UK net zero commitments, and now we want
- to keep the temperature no more than 1.5°C, and to do that, it's a big challenge. It's actually
- very complicated, and so I think the biggest challenge we have is, how can we balance
- the energy cost and efficiencies of creating low-cost and efficient, sustainable technologies,
- but where will this energy of supply, where will our materials come from so that we ensure that we
- have no carbon emission overall? So sustainability is just not only about building a sustainable
- technology. It's thinking across the box to what goes into that sustainable technology?
- What materials? What manufacturing processes and how we put things together.
- So the UK path to net zero is to make actions across four important areas,
- and the first area is this plot here, which is purple-y, and that's up to us. This will be small
- changes that we need to do in our daily life, for example travel less. I guess we've learned that
- with the pandemic. We don't need to fly anywhere just for a half-an-hour meeting. Use less cars,
- shared mobility, cycle more, eat less meat and things like this, and also improve the
- efficiency in energy and resources. The biggest of all of this is take up low carbon solution,
- and this is where the challenge, is and this is the area I'm also working on. So what can we do?
- The big things for the UK is electrification. Everything will be electric, and so we need to
- increase the energy by quite a lot, and then hydrogen is another big factor in this scheme,
- and we'll tell you a bit about hydrogen today, and also as an intermediate solution until we manage
- to build those sustainable technologies until we manage to electrify everything, we can also do a
- bit of carbon capture and storage, but even better if we do carbon capture and utilisation, meaning
- that we suck the CO2 from whatever is created - eventually we can also take it out of air once
- we get to net zero, but that's in the future - and then utilising it to create sustainable chemicals
- and fuels. Then we just need to expand on these low-carbon technologies once we develop them. Then
- the last thing here is the natural carbon storage, more forest restoring peaks and things like this.
- So as I said, one thing is clear. We're going to have a tremendous increase
- in electricity. The electricity demand could double by 2050, and
- the idea is that most of this electricity will be generated from renewables. So you see here, some
- is hydrogen. Most of it will come from renewable sources, and in the UK these renewable sources, of
- course, wind. There's a lot of wind in the UK, and so this is a very complicated and confusing slide,
- and I made this on purpose to show you that it's very complicated, but also
- we have to be optimistic because we have so many options and so many technologies available. So
- I'll try to get you through this, but it's pretty much what I said. We're still using fossil fuels,
- or at least gas, today. They emit CO2. We can capture this CO2. We can split water,
- and we can do this with electricity, with light ideally, or via classical thermal catalysis,
- and from water we can produce hydrogen. Once we have hydrogen and we capture the CO2 we
- can make a lot of good products, our most-wanted chemicals and materials, but we could also make
- this directly from CO2 via electroreduction or photoreduction using just the protons from water,
- not the hydrogen, and getting to the same type of commodities. We could also electrochemically
- reduce nitrogen from air and create our future ammonia, which will be net zero, and we could
- use this as fertiliser for agriculture, or for maritime transport. Once we have hydrogen,
- that'd be great, because maybe we'll see hydrogen planes in the future. I'm sure we will see,
- and definitely hydrogen goes into what is called a fuel cell, which can create electricity
- with only water by-product, and these fuel cells will be able to power
- buildings and also heavy-duty vehicles and trains. Of course, let's not forget batteries. Batteries
- are an enabling, absolutely crucial component of all this scenario, where they are able to
- store this intermittent renewable energy for the grid, but also for decarbonising our transport in
- electric cars. So now, of course, there's a lot of competing technologies here, but I think we need
- all of them, and we need to work on every single one of them to accelerate our path to net zero.
- Now, talking about batteries, of course we all know what a lithium-ion battery is, and I guess
- every one of you in this room has at least two if not three lithium-ion batteries at the moment with
- them. They're great. They're fantastic. They got a Nobel Prize in chemistry. They changed
- our life, and we are very dependent on them. Now, for the non-scientific audience, a battery
- is a device that basically converts chemical energy, so energy that is contained in
- chemicals, directly into electric energy. The way it does this is using some redox reaction,
- electrochemical oxidation and reduction. The first one that discovered the first real batteries,
- Alessandro Volta. He was a professor in Italy, I think at Pavia. He was on the Italian lira, but
- now we have euros, and probably was also the first professor that actually turned out to
- be useful for something. There have been many followed. So from this simple battery, which
- basically has a zinc rod and a copper rod immersed in a sulphuric acid or sodium sulphide solution,
- where zinc is giving away electrons to copper and then it generates electrons like this.
- We went to a lithium-ion battery, which works pretty much the same in the sense that we still
- have an anode that is graphite, we still have a cathode - there can be many but traditionally,
- as discovered by John Goodenough, this was lithium cobalt oxide - and you have an electrolyte.
- The way a battery works is that basically when you discharge it, so when you take electricity
- from your battery, you move lithium ions from the anode to cathode, and when you use your battery,
- when you use it to charge your laptop the reaction is inversed. So the difference between this and
- the Volta battery is that this is chargeable. This is a secondary battery, where the Volta battery,
- once you've oxidised all the zinc, the battery's dead. So this is the primary
- battery that we normally throw away. Now, you may wonder what's in a lithium-ion battery. I said
- there's an anode and cathode and an electrolyte, but actually things are very complicated. There's
- a lot of things in a battery, and because of this complexity it's just so difficult
- to really improve these technologies and also find alternative technologies.
- So as I said, there is an anode. This is graphite. There is a cathode. Let's say
- this is lithium cobalt oxide and these are glued to current collectors, things that would conduct
- electrons. The way they're glued is using a sort of a glue which is called a binder.
- Sometimes you add something else that is even more conductive to match the conductivity of
- these metal collectors and pass electrons through the anode and the cathode, and then in between you
- have an electrolyte. The role of the electrolyte is to transport ions between anode and cathode
- but not electrons, because they have to go on an external circuit. The electrolyte itself is
- complex and it contains organic solvents, sometimes two or three, and a lithium salt that
- gives the lithium ions, and these salts can vary as well. There is a separator as well in between
- that the ions go through, and as you charge and discharge the battery
- there's a lot of complicated processes happening. Your electrolyte, for example, decomposes on your
- anode and it forms the so-called solid electrolyte interface, which is a messy organic layer.
- Lithium can plate on top of other lithium that is left on here, on the anode,
- and have these lithium dendrites. That's the reason why batteries sometimes explode, because
- the dendrites go through and pass through the separator, and also the cathode can decompose as
- you have high voltages, and then you carry what's on the cathode on anode. That contributes to the
- interface formation, and it's in general complicated. That's why your batteries don't
- last very long. That's why sometimes they explode, and that's why they're still very unreliable. So
- our duty here is to make them better. Now, in lithium-ion batteries the anode stayed
- pretty much constant. We're still using graphite, but the cathode changed over time from lithium
- cobalt oxide to the so-called NMC materials, and I've plotted here cost, safety, cycle life,
- power and energy density so you can compare this. So basically this shows the capacity,
- so the higher this value is the better, versus the potential. You want your cathode to operate at the
- highest potential possible. This is a challenge because most electrolytes are not stable at these
- potentials and that's why SEI forms. Anyway, these are the material trends, and you would see
- that we're moving from the lithium cobalt oxide to more manganese and nickel-rich chemistries.
- Why we're doing this is that actually all the components that are in lithium-ion batteries are
- on the list of critical materials according to the European Union, and that includes lithium itself.
- So lithium has been added on the list of critical materials in 2020, is the latest to
- be added on this list, and I told you cobalt, high up on the list of critical materials,
- and also graphite. It's on the list of critical materials, and many other things that you use
- in batteries, it's on this list of critical materials, and the way this is classified is
- economic importance. The more we use these metals the more they'll be, versus the supply risk,
- meaning that there's not a lot of these materials, and I'll explain you a little bit. What is clear
- is that the demand for battery manufacturing is increasing and increasing, and these are
- some predictions here. You would see that by 2030 we would increase to 2623 gigawatt hours,
- and most of this will be due to electric mobility, as you could see here. Some of it for storage,
- but of course we will ban all the petrol cars very soon and everyone will drive an electric car.
- So there's a lot of pressure and demand on batteries, and as this demand increases, so
- our concerns about where are we going to get these materials for batteries. So these are some other
- predictions of raw material demand in kilo-tonnes per annum on a base case, also by 2030, and you
- could see that all of it is going to increase by quite a lot. That includes nickel itself,
- which at the moment is not on the list of critical materials. As I said,
- we are moving from cobalt to nickel-rich chemistries and we might have a problem
- with nickel very soon. Also the grade of nickel for batteries is nickel grade one, which is quite
- important. Another problem with these materials is not that we don't have enough lithium in this
- world. It's where it's geographically located, and the easiest-to-mine lithium is from brines,
- and these are only located in South America, Bolivia, Argentina and Chile.
- Cobalt is, as you might know, is all in the Democratic Republic of Congo. There are a lot
- of ethical issues against mining cobalt, child labour and so on, and so is graphite. Most of it
- is in China, and so we don't have enough graphite in Europe. Well, there's some in Russia but that's
- also complicated at the moment. So if you think of sustainability of lithium-ion batteries,
- it's not that lithium-ion batteries don't have CO2 emissions. If you look at this graph,
- you look at the CO2 emissions across the lifecycle of lithium-ion batteries - and these
- are in different countries China, EU and US - and you see most CO2 emissions come actually from
- manufacturing the materials for batteries and putting them together in a battery.
- So in Europe in 2018, for example, the CO2 emissions from lithium-ion battery production
- was about the same as Holland is emitting today. The good news with lithium-ion batteries is that
- you mitigate the CO2 emission as you use your car, but that's only if your electricity comes
- from renewable sources, and that's where this difference comes between China and EU and US,
- because the EU and US has more renewable energy compared to China, which is pretty much based
- on coal. So the question, and I guess the holy grail of all battery research is, how can we
- address sustainability in batteries? How can we make the dream battery that is both performant,
- sustainable and low-cost? This is a very challenging thing to do, and two of my
- amazing postdocs, Heather - who is here? I've seen her earlier. I don't know where she is Yes,
- there - and Maria, who unfortunately can't be here because she had a bike accident - I wish she would
- be here - they've actually wrote an amazing essay on how we can diversify batteries beyond lithium.
- It's, I think, still free if you're interested in reading it, and they also come with some sort of
- greener battery specifications, of how we can make batteries greener. So in my group that's what my
- research is a lot about. How can we move beyond lithium-ion? How can we make other different
- battery technologies? I'll tell you a little bit about this other battery technologies. I'll
- start with sodium-ion batteries. So sodium-ion batteries, they can be a very low-cost solution to
- replace… Not replace because lithium will always exist, but coexist with lithium batteries. Why
- is sodium more appealing? Unlike lithium, that I said is very unevenly geographically distributed,
- sodium is all over, and in particular in Europe we have lots of salt mines.
- The nice thing about sodium is, as I said, in the battery you also need a current collector to put
- your anode and cathode, and for lithium you have to use copper for the anode because lithium forms
- an alloy with aluminium, but sodium does not. So you can use aluminium on both sides,
- and so current collectors will be cheaper. Basically they work exactly the same, or more
- or less the same, as lithium-ion battery. So if you are lithium-ion battery manufacturer you won't
- have to change much. There was a big announcement towards the end of last year with the biggest
- EV company, CATL from China, announced that they're going to launch a sodium-ion battery car
- in 2023, which would have slightly lower 160W/kg, I believe with lithium-ion around 200 and above,
- but will be able to charge in 16 minutes. This is very fast charging. This is the advantage,
- one of the advantages, of sodium-ion batteries. As I said, a sodium-ion battery works very similar to
- a lithium-ion batteries. I showed you how lithium battery works. Well, you also have an anode,
- a cathode and an electrolyte. This electrolyte has instead a sodium salt, and basically you shuffle
- sodium ions between the anode and the cathode, exactly as in lithium-ion batteries.
- Now, the material trends in sodium-ion batteries, there's been quite a lot of work on cathodes,
- which is the positive electrode, and a lot of this work has been inspired
- by work on cathodes for lithium-ion batteries. The nice thing about cathodes for sodium-ion batteries
- is that they don't use in general any critical materials. You could use things as iron and
- manganese, which makes them more sustainable by default. There are more challenges about
- finding the right anode, and that's where my group is working on. So as I said, in a
- lithium-ion battery you use graphite as the anode. Unfortunately graphite cannot store sodium,
- and the reason is not necessarily that sodium is bigger than lithium
- because, potassium is even bigger and it happily goes into graphite. It's the interactions between
- the sodium and the energetics with graphite. It just doesn't quite fit, and so because of
- this you need to find different materials to use as an anode in sodium-ion batteries. Graphite
- is a perfect type of carbon allotrope where basically you have a graphene - everyone heard
- of graphene, there is a big boom in the UK - so there's many graphene layers on top of each other.
- If you don't have this perfect structure in graphite, and you have these graphene layers
- randomly oriented with each other - you can imagine it like a house of cards - that you
- put them together and then basically it's this situation here where you have a bigger distance
- between these graphene layers than in graphite, and you also have a lot of closed pores in
- between. Now, sodium happily goes into this type of material and my group, we did quite a lot of
- research to really understand how we can maximise the amount of sodium that could go into such
- a disordered type of pseudo-graphitic carbon, and we try to understand the mechanism of this.
- So coming back to my discovery during my postdoc, which was by accident, this hydrothermal
- carbonisation which turns biomass or biomass derivatives into carbon, when we did the same
- we created this spherical carbon, and then we wanted to tune all the structures of this carbon.
- I'll show you in a minute what I mean by tuning the different structures into these materials.
- So what I mean by tuning the structure is that in graphite, as I said, there's these graphene layers
- perfectly parallel to each other, and you have a distance of around, let's say, 3.4, or somewhere
- between 3.4 and 3.3 angstroms between them. Now in these disordered carbons you have different
- spacing between these graphene layers, and so we can tune this spacing between
- these graphene layers by tuning the different temperature at which you prepare these carbons.
- Also, we can tune the pore diameters in between these graphene layers, and we also could play
- around with defects. So imagine this house of cards, or one card that could have some oxygen
- functionalities or other imperfection. This seems to be quite important for storing sodium,
- and if you look around you would see that one situation performs the best. This is when we have
- this particular interlayer spacing here, close to 3.7 angstrom when we have a pore diameter around
- somewhere between 2 to 3 nanometres, and then we have a sweet spot for oxygen on these graphene
- layers. So with the help of [?Chang 0:38:00.7], I saw she's here and Amelia, she should also be
- here - yes, she's sitting there near. near Heather - we've been doing some modelling, DFT modelling,
- to calculate the theoretical capacity if we would have oxygenated effects, and we saw that
- this would be different from our experimental. Also, she modelled what would be the ideal
- interlayer spacing between these graphene layers for sodium to intercalate, and it seems to fit
- very well with our situation. So we've kind of concluded here that defects are important, but
- there is also some intercalation, and this is what happens at the first part of the sodium storage
- in carbon, which is called the sloping region. Then we wanted to understand the role of pores,
- because of course we thought the bigger pores we have, the more sodium can go in and you
- plate it as metallic sodium. So with the help of Claire Grey and Chris, who's been wonderful,
- we did some solid-state NMR, and we've seen a peak for metallic sodium into these materials,
- but it seemed not to correlate really with the pore size. So we were wondering what's happening.
- Anyway, we did some more NMR and we figured out that there's actually no connection between the
- pore size of our carbon materials and the shift in this metallic peak, and it has to
- do more with the way sodium interacts with the aromatic structure of this carbon materials So,
- based on this, what we've concluded, with a lot of characterisation, with a lot of electrochemistry,
- is that there is this sweet spot here where the interlayer spacing is large enough for sodium to
- go and sit as metallic sodium in these pores, and that's where we store more sodium, but actually
- if we have larger pores, it doesn't mean that more sodium can go through because the pathway to these
- pores is closed, because now the interlayer spacing between these graphene layers is too
- small so the sodium can't get through the pores. If we open up, so this is the same material, this
- material here that performs rubbish - basically there is no sodium storage, no plateau - once we
- open up the pores you see that you open up the capacity. So our theory seems to be right. Then
- my PhD student, Hande, has been proven further this theory where she created carbons with
- the right interlayer spacing between these graphene layers and larger pores, and we could get
- the impressively high capacities. So what is happening is something… I'm a very bad draw-er,
- but it's something like. The sodium goes in. You need to have enough interlayer spacing
- for metallic sodium to go in. This storage here is very fast in the sloping region, and you can
- make this even faster by putting more oxygen or defects. So sodium can be fast-charging batteries,
- and once it's in the pores you can increase the capacity, and what you should actually avoid
- is having blocked sodium in the pores or too-small interlayer spacing for the SEI formation.
- I'll skip this, but I told you that in batteries it's not only important to work on materials,
- but it's also important to understand the interface and actually the electrolyte. Just
- by simply changing the sodium salt and the solvent it will give you a completely different interface,
- and this is not the interface you want. You want a nice interface like this. So basically again
- Amelia helped us do some simulations here, and we figured out that if you use the right electrolyte,
- which is an aether-based electrolyte, you get a very, very nice interface, and if you
- use a sodium perchlorate with a carbonate electrolyte you get a terrible interface.
- So now you may wonder, what are sodium-ion batteries good for and why do I bother so much?
- Well sodium are going to be fantastic for the grid storage. They're very low-cost
- compared to lithium, so they're going to store our intermittent renewables. They're great for
- short-distance mobility. There's a lot of these things in London today, e-bikes and e-scooters,
- low-speed EVs for city transportation, and I said they have the potential to be charging faster than
- lithium. So that was the story about sodium. I'm kind of running out of time, so I wanted
- to tell you a bit about… After I said that how we shouldn't be using lithium, I'm going to go
- back and tell you about lithium-sulphur batteries. Don't worry, I'm actually going to
- minimise the amount of lithium into these batteries, and that's what we're trying to do.
- So as I said, sodium batteries are great. They're low-cost, but they're never going to be
- better than lithium-ion batteries. Lithium-sulphur has the potential to be. So this is how much
- energy can be stored per kilogram versus how much energy can be stored per litre. So that
- means if you have a battery that is good here, it will be a very small battery that will act
- amazingly well. Now, lithium-sulphur batteries work very different from this
- rocking chair configuration, lithium-ion, sodium-ion. There is more chemistry involved
- in here in the sense that you oxidise lithium to lithium ions that go through the electrolyte and
- interact with the sulphur cathode, and what you want is this Li2S to be formed, and then you want
- this to revert back to sulphur and lithium. So this conversion is actually more complicated
- than it should be. So you don't unfortunately go directly to Li2S, but you go through a lot
- of these polysulphides intermediates. Some of these polysulphides are actually
- soluble in your electrolyte, so they're going to plate back onto your lithium anode. You're
- going to lose your cathode. It's called the polysulphide shuttling. So lithium-sulphur
- have a lot of problems in the sense that their longevity is limited, and also you get a lot of
- dendrite formation on the metallic lithium anode, because now you use a piece of metallic lithium.
- So we have some funding, the only funding I have - I can complain now because I'm here giving a talk,
- from the Faraday Institution - at these two amazing girls, Heather
- and Sam, and what they're trying to do is to make a self-standing lithium-sulphur battery. So
- we like biomass in our group, and we do a lot of carbon materials from biomass. Here,
- instead of using this hydrothermal process, I use something else that is more like a spider
- making fibres and we use something from plants which is called lignin.
- So plants have cellulose and lignin - Jason knows that - and hemicellulose. So the lignin
- is the one that gives structure to the plants. Anyway we can extract… We can't
- extract it. Jason can extract ,it and then you can use this lignin to create these
- carbon fibres. You make a fibre using some electrospinning by applying some potential,
- as I said, like a spider web and then you carbonise to get a free-standing carbon mat.
- That's our technology for making free-standing lithium-sulphur
- batteries. So this is how our fibres look like. What Sam is trying to do
- is to understand if you can actually plate metallic lithium on this 3D current collectors
- in a way that, rather than using a big chunk of metallic lithium, you use just a few lithium
- nuclei deposited on these carbon fibres and that's your anode, and so you then prevent the
- dendrite formation and so on. We just started this work.
- So yes, we're just looking how this lithium is plated on these carbon fibres, at which potential
- if it goes, where it goes. It seems that it goes a lot on the separator. As I said, we're at the
- beginning, but the idea is to have this carbon fibre mat with a bit of lithium nuclei and to pair
- it with this cathode, which is the same carbon fibre where Heather is trying to deposit directly
- Li2S8 onto these carbon fibres to make a cathode, and this cathode seems to be working very nice.
- Remember that before for sodium-ion batteries I told you the capacity was about 300.
- Now we can reach 1000 milliamp hours per gram. This is normal for lithium-sulphur,
- and you could see how this Li2S is formed, and then it disappears again. So this seems
- promising, but again we're really at the start. The idea where we're trying to go with this is,
- can we make a structural battery? Can you imagine one day, since you get a very high energy density,
- an aeroplane wing made of a lithium-sulphur battery, which is made of this carbon fibres
- that would be also able to store your electricity, and of course if these carbon fibres are made from
- a biomass it would be even better. Of course, this is a long-term dream, but it would be nice.
- I told you a lot about batteries, but the last slide I promise I have on batteries is
- that if it wasn't complicated enough with lithium and sodium and lithium-sulphur, we
- have the potential to actually use really abundant metals such as aluminium, magnesium and calcium,
- where this would be the anode, but the challenge is to discover a cathode that would be able to
- store these multivalent metals, which is very difficult because they're very highly polarisable.
- They interact strongly with pretty much everything, and so I have Anastasia that
- started to look at aluminium-ion batteries, but we're not going to get into details there because
- things are very complicated. She has a hard job to do. Now, I was talking a lot about sustainability,
- sustainability, sustainability, but how do you actually quantify sustainability? Can you do it?
- There is a method that is called lifecycle assessment, and I'm not going to explain you what
- lifecycle assessment is. I just want to show that there is a database depending on the material you
- use that tells how many trees have been cut, how much CO2 have been created to mine the material,
- how are the processes has been done and so on. The easiest is to quantify the global warming
- potential, but there are other factors you can quantify, and so we did this for one of our
- anode for sodium-ion batteries. There is a way to do it.
- It's complicated and it's pretty inaccurate at the moment because those data are very variable,
- so quantifying sustainability is difficult. The very last minute I have left I want to also tell
- you a bit about green cat, because I told you a lot about green bat. I'll be quick.
- I just want to show you how a hydrogen economy would work. As I said, batteries are important
- because they can store intermittent renewable energy, but so is hydrogen. The scenario
- for hydrogen, well, we might have different colours of hydrogen. There's grey hydrogen.
- That's the bad hydrogen. That's the hydrogen is produced from gas reforming or coal reforming.
- It generates a lot of CO2. This is how most of our hydrogen is produced today. That's why it's highly
- unsustainable, and our chemical industry that relies heavily on hydrogen, it's so CO2- heavy.
- There's the option of blue hydrogen that's doing exactly the same thing but capturing the CO2.
- There is now turquoise hydrogen, which means that instead of using gas to produce this hydrogen,
- or coal, you use biomass, you do carbon capture and storage, and there is green hydrogen,
- and that's what our dream would be. So the use for hydrogen is across all these areas. Hydrogen
- could be used in transportation and power, in fuel cells, to create clean electricity, or
- to create alternative fuels. As I said, you could use hydrogen and CO2 to create alternatives to the
- fuels we know today. You may have heard that there's big plans of replacing all the gas in
- our boilers with hydrogen, and also heat pumps. You use hydrogen in industry to create chemicals
- and materials. You use hydrogen to reduce nitrogen to make fertilisers in agriculture.
- The plan for the UK is to go from currently 27 terawatt hours to 270 terawatt hours. That's a
- huge jump in hydrogen production. Most of it will be still by gas reforming with CO2 capture and
- storage immediately by 2035, and there will be some increasing green hydrogen via electrolysis.
- As I said, this is where hydrogen is going to be used. There is a UK hydrogen strategy if you're
- interested in reading it. Ambition is to deliver five gigawatts production of green hydrogen,
- and this is where some blue and green hydrogen will be located around the UK. It's about
- harvesting all the great power of wind we have in this country, and that's where the electricity
- will be produced to generate this green hydrogen. I stole this slide from Ifan without asking him,
- but I did ask him before so it should be fine. I just wanted to tell you there's different
- technologies to produce green hydrogen, and it's all called electrolysis. The most
- trendy and the most efficient is this proton exchange membrane electrolysis.
- Basically what you do in electrolysis is, again you have a cathode and you have an anode, as in a
- battery, and an anode, deoxidised water to oxygen. This creates protons. It's moved to the cathode
- via proton conductive membrane, and here you have a catalyst and you generate hydrogen.
- This is a cross-section of an electrolyser. So basically you have here basically what I said,
- the membrane, and then you have your catalyst here that is good for producing hydrogen as the
- cathode, and then the anode is the complicated part where you have an iridium oxide catalyst
- supported on a porous titanium., because this reaction is very
- corrosive and nothing is really stable. Now the thing we should be worrying about is
- this oxygen evolution reaction happening here. So, water oxidation. I'm not going to explain
- what overpotential is although there are many scientists here, so you all know. It's
- basically the difference between the theoretical thermodynamic potential and the potential at which
- this reaction takes place, and as I said, for oxygen evolution reaction this is quite high.
- That's why you need iridium oxide, which is a very expensive and critical material,
- and the titanium porous layer with the catalyst make the cost of green hydrogen very expensive.
- Now what we're doing in our group, and in according to the UK government is,
- what if we make hydrogen by making something else useful at the same
- time? When you oxidise water you create oxygen. It's not very useful. You use iridium oxide. So
- can we actually decarbonise across the sector? That's where another of my amazing postdocs,
- Hui, is working, and she's working on biomass electrolysis. So rather than oxidising water
- you oxidise a biomass derivative, whatever it is, partially oxidised to some very useful chemicals,
- and then it's easy to evolve hydrogen, as I said. So what she did is, she managed to
- actually produce green hydrogen and green plastic at the same time. So the way it works is,
- she's using glycerol, which is a waste from biodiesel industry, and there's two paths
- to oxidise in glycerol, and we want to follow this path which we want to make this molecule.
- Doesn't matter how it's called, and once we make this molecule we take some inspiration
- from homogeneous catalysis and we use the Lewis acid step and a Bronsted acid catalysed step,
- so we combine electrocatalysis with homogeneous catalysis and we produce lactic acid.
- It's great to produce lactic acid. You may all heard of polylactic acid. You probably have all
- been annoyed with the biodegradable bags for our biodegradable waste which melt before you take
- your garbage to the bin. So that's polylactic acid, where you could make it better than this.
- All the renewable cups and everything is made of this. It's a biodegradable plastic.
- So basically we can make glycerol, a waste, to monomer to make biodegradable plastic,
- and produce hydrogen at the same time. Not only that, but what we also do is we take PET.
- You all know PET from the Coca-Cola bottles and the Starbucks cups. What we do with pet,
- we ball mill it with some sodium hydroxide and we can actually very nicely recover the monomer from
- which PET is made, which is terephthalic acid. So you could make a new PET bottle, so we could have
- a circular recycling of PET. The side you make ethylene glycol.
- This molecule is actually quite similar to the glycerol molecule. So basically what we do is,
- we produce green hydrogen from this, so we can have a recycled PET and green hydrogen.
- So basically we also work on production of green hydrogen with green plastic in a one-step process,
- and I'm done. I just wanted to tell you that once we have this green hydrogen we also work on fuel
- cells, and to confuse you enough fuel cells, as I said, is that technology that uses hydrogen now
- to produce back water and clean electricity. It's kind of the reverse of an electrolysis.
- Again, most popular is PEM fuel cell. So here, once you have hydrogen, this hydrogen is oxidised
- to protons that are conducted by a membrane, an electron - that's your electricity - and
- then basically here you reduce. You have oxygen reduction at the cathode
- which, as oxygen evolution in an electrolyser, is highly inefficient and
- you need a catalyst to lower this overpotential. Now we all know that platinum is a critical
- material. As I said at the beginning, it's high up on the list of critical material. It's mostly
- located in South Africa. So what we do in our group is using the same type of carbon technology,
- but this time taking inspiration from enzymes to create this iron, single sites coordinated to
- four nitrogen or six nitrogen supported on carbon, and the idea is to take inspiration from nature.
- My lobster disappeared for some reason. Oh, here it is. So we've been actually taking a
- lot of inspiration. Actually, we've been using wood. We've been actually using lobster waste,
- which is very nice. That was back at the Max Planck, where we got the lobster for free, Omar.
- We've been also using pretty much of albumin, which is egg white and sugar, and we've also did
- a coral-like inspiration, so trying to make this catalyst very porous, and on them we support these
- enzyme-like materials. [Unclear word 0:59:18.7] has been doing quite some nice work on this
- during his PhD. He graduated yesterday officially, where he's been putting single sites,
- and basically you see here this is the platinum. Platinum is black. It works the best. What you
- need to look is this point here where you start getting some current, and the amount of current.
- We're not quite as good as platinum but very close. He's been also with the help of Dan,
- who I see he's sitting there, at UCL, in a sample of fuel cell and it works quite nicely.
- Currently we're trying to optimise these materials with Angus and Jesus. They're trying, instead of
- one single iron, to put two iron close to each other and see how these two irons can influence
- the catalysis of this oxygen reduction reaction. There's a lot of intermediates involved and that's
- what the catalyst does. It just breaks the linear relations between all these intermediates to get
- the minimum overpotential and maximum current. So we're still working on this. So fuel cells are
- great because you could, as I said, make cars with them. That's our famous Imperial hydrogen-fuelled
- car. You can make trains. There are already buses working on hydrogen all around London,
- and why not? Maybe in the future we will all fly a hydrogen-powered aeroplane. So I am now at the end
- of my talk, and of course the acknowledgements. It's the most important part. I'm very grateful to
- have also worked with really amazing people. They have been doing everything,
- and basically this award is really for them, not for me. That's why we're going to spend the £1,000
- maybe later on in the pub. I have a big group. These are some pictures over time,
- and you may have noticed that I always worked with a lot of women, a lot of wonderful women.
- I think it is true that having more women PI attracts more amazing women
- scientists and this is how we can fix the leaky pipeline. There's so many people I want to thank,
- and I am sure I forgot some, in particular the Imperial crowd. I didn't have more space
- for it but yes, I would like to thank Ifan of course for all his friendship and collaboration.
- Mary, James, Jenny. I don't know if Jenny is here. There she is, and I'm not sure if I'm allowed to
- say that, but she was my nominator for this award so I'm very grateful for her. Thank you. Jenny.
- Nilay, my first head of the department for being such an inspirational person. Omar,
- my current head of the department for being such a wonderful head of the department, really
- wanting the best possible for our department. The list is very long. I'm not going to read all
- of them. Of course, the Queen Mary crowd. I can see Joanna, Jo and Petra here. They are amazing
- and they're doing very well. The UCL crowd, Dan, Paul and all [unclear words 1:02:41.8] for being
- among the first ones to introduce me to the UK academic family when I was here very lost,
- and James is also here. He was the only academic I knew when I moved to the UK, and he was an amazing
- mentor for me. Of course, everyone else, and Misha that I see here. I'm so happy you moved to Kings
- and I hope you're going to stay for a bit longer. Don't go anywhere. Claire
- for all the NMR. Lyudmila, Chung, the Birmingham crowd, Emma, Phoebe, and Zoe,
- my collaborators that are still in Berlin, Spain, China, Japan. I realised I don't
- actually work much with American people. Probably I should change that, or not.
- Of course, all the institutions I've been through, everyone that gave me their funding,
- and of course my family. My dad, who is no longer with me, but he would have been really proud of
- me today. He was a scientist himself. My partner Renato, and our first cat and our adopted cat,
- and that's my new dog. My new dog that my mom got, and I'm in love with the dog after
- two visits to Romania, so I thought I'll put him there as well. Her. Thank you very much,
- and I'm not sure if there are questions. Probably spoke too much already. Thank you.
- Thank you very much, Magda. That was super, a great tour around a very extensive and
- very impressive body of work related to the topic. So we have time for some questions.
- Who would like to start us off with a question? I'm sure someone
- has something they really would like to ask after that really exciting, stimulating talk.
- Yes, I think we have a question here, and then at the other side, and I'm going to pop down and
- grab this iPad while you're doing that because I know we have people online as well.
- So if you're using Slido online you can put your questions in that format. Please, go ahead.
- Magda, a question close to my heart in terms of recycling, I think you know,
- lots of effort going into battery recycling. If it works and we do recycle lithium for example,
- and the cobalt and so on, should we give up on the other metals and just stick with lithium?
- No. I think it's important that we start recycling lithium and cobalt,
- absolutely crucial, because it will take some time until we develop
- this emerging technology. So it's a bit like parallel between should we still do CO2 capture
- or not? Yes, we should do it, but also in the long term I think developing new technologies is
- equally important. Also, these new technologies need to be recycled at some point. So
- if we learn how to recycle lithium and cobalt and all these precious metals, we would then know what
- to do with the end of life of these new emerging batteries, because they also have to go somewhere,
- even if the economics are not so appealing. I think with batteries the recycling starts
- with putting things together better than they are currently today. Manufacturing for disassembly.
- Okay. We have a question over here, and then one over on your right. My left.
- It's absolutely fascinating. I just wonder, you hadn't really included anything about atomic
- energy, I thought. I don't know, maybe you did it right at the beginning in one of your diagrams
- and how you see that fitting in. Also, as a complete non-scientist, the amount of water
- that you use to make some of your hydrogen and so on, is that in conflict with the
- ever-decreasing amount of water that's available for sustaining life?
- Yes, they're both very good points. On the first point of atomic energy, I'd rather not comment
- because I absolutely have zero expertise in this area. I think, and that's my non-scientific
- personal opinion, that is important to have some nuclear energy in the mix. As you could see, the
- scenarios for the UK are mostly renewables. Other countries such as Germany are completely dropping
- nuclear energy. Again, this is really not at all my expertise, so I don't really have a scientific
- opinion. On the second one with the water usage, yes, you're absolutely right, and water is also a
- big problem. As I said, there's this lifecycle assessment which you can actually quantify
- where the biggest environmental impact comes. A lot of times it comes from the water utilisation,
- and at least for my hydrothermal carbonisation where you use water to make this carbon, you can
- actually recycle the water. For water electrolysis you could use water with desalination close to sea
- water and things like this. But yes, electrolysing something else than water is also very good.
- Thank you very much, Magda, for a wonderful talk. So first of all,
- I think it's a great testimony to the saying diversity and insights into many different
- countries and systems fosters excellence. I think your CV and the performance of your group bears
- credit to this. So thank you for this great introduction to not only your
- entire history and that of your group, but also to the matter. Now, to the topic itself.
- The EU wants to decarbonise all relevant industries by 2030. This is the frame in which
- we will be operating. Our industrial cooperator, Varta, wants to decarbonise even earlier.
- So how are we going to go about… I mean, one of the arguments being made here is that you're
- weighing performance versus sustainability.
- I think the way forward should be really that we convince our industrial partners and the
- end consumers that green is not necessarily worse and more expensive. Green can be better.
- So I mean, how do you see the way with this proposed technology to go into this particular
- direction? Pricing in sustainability as a value-added thing. Thank you.
- I mean, I see it. Please do convince the industry to do it. I don't know, it's just
- very complicated. All the big industries have made this commitment that they are going to reach net
- zero by 2050. Companies like Shell, BP, BASF. Are they actually going to do it by just giving
- a bit of money to universities to do something green? Well, I'm not sure. This is just very
- debateable, and that's something that I again don't have an answer. If there's any
- industrial person in the audience or some governmental person they're best entitled to
- answer this. It's easy to set goals, but how are we going to do it? Well, we shall see, I guess.
- Okay, I've got a question online for you here. What about electro-polymers used as electrodes,
- or other applications within fuel cells? So I guess it's looking at polymer-based electrodes.
- I mean, maybe Jenny can answer this. I guess polymers are great, but conductive polymers
- are not actually that conductive. Again, I'm not an expert in polymers. I don't know. Yes, there
- is a possibility. If you don't have 100 million steps doing the polymer to work well with a lot of
- solvents in between, if you can have that really easy-to-make polymer in one step, that'd be great.
- Okay. Any more questions from the floor? I've got another one here for you, but
- let's see if anyone else wants to ask anything out here first. Don't be shy.
- There are no stupid questions, remember? Oh well, not until Dan put his hand up. Sorry.
- Thank you, Peter. I really enjoyed your back history. That was really, really entertaining.
- Thanks for that presentation. I know you've been very supportive of female scientists and
- young scientists, and obviously lots of people here to show that. What advice would you give
- to someone setting out to do a PhD now in this electrochemical advanced materials kind of area?
- Well, I guess start before the PhD. Pick wisely. I haven't picked that wisely, but still I ended up
- okay, but it's better if you pick wisely. Make sure that this is really what you want to do,
- and that's the group you want to work, and while you start doing I guess just don't be afraid of
- doing new discoveries. If you come across something else
- that your boss might not agree, you should still try to do it. Get as many
- mentors and supervisors as possible so that you can talk with a lot of different people, and
- just be creative and proactive, and don't be shy. Just go for it. That's the advice I would give.
- Okay. Anyone want to ask a last question before we let Magda off the hook and let her have a drink?
- No? Okay. Well, let's thank her once again.
- Again, I would just like to take the opportunity
- to congratulate you on the award of the Kavli Medal.
- Thank you.
- Good. Thank you all very much.
Batteries and catalytic processes are key for delivering the green industrial revolution by storing the intermittent renewable energy and releasing it when is needed most.
The Kavli Medal and Lecture 2022 given by Professor Magda Titirici.
It is imperative we mitigate and then reverse carbon emissions. COP26 recently took place with the goal of a global commitment to keep a maximum of 1.5 C warming within reach.
A green industrial revolution powered by many sustainable innovations evolving in parallel is essential. Yet we need to make sure that this new revolution happens sustainably and does not create more damage. We must learn from past mistakes and learn how to see the bigger picture rather than immediate goals.
Batteries and catalytic processes are key for delivering the green industrial revolution by storing the intermittent renewable energy and releasing it when is needed most to decarbonise our economy across various sectors. Yet, battery materials and catalysts for various sustainable technologies (such as green H2 generation and conversion) are facing real challenges as they are based on critical and expensive metals.
Professor Titirici’s research group and collaborators are working towards addressing this important challenge of creating sustainable materials based on widely available resources while creating a circular economy of recycling biowaste into advanced materials and implementing them in sustainable energy technologies, from new battery chemistries to important catalytic processes using renewable electricity for H2 production and use.
About the Royal Society
91TV is a Fellowship of many of the world's most eminent scientists and is the oldest scientific academy in continuous existence.
/
Subscribe to our YouTube channel for exciting science videos and live events.
Find us on:
Bluesky:
Facebook:
Instagram:
LinkedIn:
TikTok: