Batteries and supercapacitors for electrochemical energy storage by Patrice Simon

[Music] the organizers asked me to do the talk in English I'm gonna switch in English for the rest of the talk I hope it's fine for most of you I'm gonna go through two different main systems chopped batteries and super capacitors so the topic today will be to try to describe as much as possible again a state of you're out and the next challenge is batteries and super caps are facing so first of all you have here what we call a revenue plot which shows the specific power there's a specific energy for different electrochemical energy storage devices so this is more or less here the power capability if you make a parallel between this raggedy plot and vehicle versus acceleration and this is the range for pure electric drive so here on one side of a revenue plot you have capacitors which are mainly power devices with very small energy densities devices and time constant of 1 millisecond very high power no energy on the other hand you have here batteries high specific energy up to 250 watt per kilogram for lithium-ion batteries and medium or low specific power batteries again are for long time the power delivery after low current so no real huge power and to bridge the gap between capacitors and batteries you have here super capacitors which are high power devices 2030 kilowatt per kilogram medium high energy means 5 water per kilogram 40 times less than batteries from lithium-ion batteries and this defines the time constant of about 5 seconds and just to show you here a comparison with a thermal engine condition you have a factor of 15 between the batteries and the energy density of batteries and energy density of gasoline so here you have more or less on the Raggedy plot the position of the thermal energy okay I'm gonna start the topic by batteries we start with basic things about batteries switching to lithium-ion batteries and perspectives and then I will move to super caps and I will give a few words about the French Network on batteries we are animating with Rama Itasca so very basic principle on batteries what is the battery you have here two very schematic alpha battery you have one electrode here a negative electrode positive electrode and electrons are exchanged between the negative electrode electrons leaves negative electrode and goes to a positive powering your device at each electrode you have what we call an active material an active material is the material which is going to be able to exchange electrons through overload at the positive electrode during the discharge you have a reduction reaction which is a chemical reaction which is a conception of electron which is thus an electrochemical reaction and this electrochemical reaction this reduction is achieved at constant potential t plus which is a thermodynamic data and then you can associate this redox reaction the capacity the capacity is the number of Faraday's the number of electron exchange per mole of oxidant so you can define here milli ampere how a per gram which is again the number of charge a material can deliver divided by the number of electrons when number of electrons you can exchange with it you have the same at the negative electrode at the negative electrode you have a very positive negative electrode sorry you have an oxidation reaction so you release electrons electrons here are then consumed to be positive and you define a negative electrode potential and a capacity of a material in milli ampere half a gram and how does it work when you discharge a battery this is voltage versus time or vs. number of lithium anyway it's not a big deal so this is a constant current discharge voltage versus time you discharged battery at a constant potential which is a cell voltage difference between positive and negative and then when you recharge you do the opposite so the capacity of a battery multiplied by here the cell voltage gives you energy density okay and rechargeable cells are called accumulators now we are everybody use forward batteries for rechargeable cells so basically batteries key materials the active material at the positive electrode which defines a specific capacity the potential cell voltage and then very energy so now let's move to lithium ion batteries lithium ion batteries are the most breaking through discovery of the 20th century in terms of batteries so it's about three to six times energy density of a lead acid battery how does it work at the negative electrode you have graphite graphite anode so you can view a graphite anode now as a stacking of graphene layers which is more sexy so you have graphene layers here and in between the layers this is carbon okay in between the layers you are going to intercalate lithium ions for instance here you have six carbon here carbon ring plus one lithium plus an iron plus one electron is going to give this compound LIC 6 but here in this material lithium is lithium ion okay it's not lithium metal this is a carbon which is going to ever receive a decrease of oxidation state so this is what we call relieve him iron intercalated graphite and this is word does Bolivia mine battery name come from so this redox reaction so intercalation of lithium ion into the graphite here is achieved at very low voltage vs. lithium 0.5 and gives the capacity of 362 million per per gram so this is today the negative electrode that you have in your cell phones in your laptop's whatever you want at the positive electrode this is eliminated cobalt oxide which is the beginning of a valium and battery it's a lithium cobalt oxide and during for instance the charge of a discharge you are going to exchange lithium plus ions so during the charge here you are going to remove leave some plus ions from the co2 structure and this Leafeon plus ions are going to be intercalating into a graphite electrode and then here you discharge and when you charge you can exchange 0.5 lithium for one Li co2 so this defines the capacity of 177 million per hour per gram and the cell voltage is difference between the positive electrode negative electrode something is missing here is about 4.2 volts lithium so the cell voltage of lithium ion battery is three point four seven volt and the capacity is 60 M per hour per kilogram energy around 200 watt hour per kilogram but when we talk about lithium ion batteries it's a big big big family you see all of these are lithium cells and lithium ion batteries that can be rechargeable are just here on this left corner so I'm going to go into a bit into the details of current state of your lithium ion batteries there is no one lithium ion batteries you have several lithium-ion batteries depending on the chemistry the chemistry of a cathode defines the name of a battery okay so we're gonna see three different kind of materials 2d materials 1d materials and 3d spinnin structures so historically speaking the first material which was used for lithium ion battery is the lithium cobalt oxide what is what is the lithium cobalt oxide it's a stacking of SiO 6 octahedral stacked over C axis and in between these layers here this is this is called the 2d structure two dimensional structure you have lithium plus ions and during for instance with charge you are going to remove Bolivian plus from the inter gab distance and exchanged electrons so this is this reaction you oxidize lithium co2 into lithium 1-6 co2 plus x DM plus plus six electrons and this is what happens you have a cell voltage this is the time at constant current of a capacity and when you discharge when you remove the lithium ions here you end up to a point here at four point seven volt but what is very important to understand is that as long as you remove lithium ions more than 140 million per per gram here this is irreversible what does it mean it means that when you have removed more than 0.5 lithium structure of nico two changes and then you cannot recover the structure so you are limited in capacity to 0.5 divyam this is the first drawback of lithium cobalt oxide but the key here is the thermal issue when you are going to heat Li co2 oxide beyond 170 Celsius degrees you are going to breaking a brick of cobalt oxygen bound and this breaking is going to reduce lot a lot of heat and this is called the thermal runaway of a battery means as long as you go beyond 160 Celsius degrees the battery goes into thermal runaway it means that the cell temperature can reach 800 Celsius degrees and you cannot extinguish a fire this is what you call what is called valium fire it was one of a problem of Dreamliner in fact it was very problem of a Dreamliner so people since 20 15 years I've tried to tackle the issue of safety and to make long story short they end up with they tried to replace cobalt because a cobalt problem confirmed cobalt oxygen bound they try to replace cobalt with over active materials and they end up with a solution of what is called very placed one third I mean two third of cobalt with one thread of manganese one third of nickel and this this nickel is nickel to means that it can be oxidized into nickel to nickel free nickel for this manganese is plus four is not active not active at all so it means that you replace a part of a cobalt with one inactive material but with another active material which can be oxidized so that in fact you don't lose a lot of capacity but you have something which is family speaking much more stable so today most of your laptops are using NMC and I'm C stands for nickel manganese cobalt cafard so this is recovered which is used and you have also what is called NC a nickel cobalt aluminum doped but Morrissey's always is nickel cobalt oxide based systems second time of cathode is what we call LFT lithium iron phosphate this is just an IPO for which is a mineral you can find it in in Seoul iron phosphate and you have a intercalation reaction of lithium plus into Fe po4 so this is really interesting because it's a second type of chemistry why it's completely different because first there is no thermal runaway there is no more cobalt oxygen bounce second there is a very flat constant voltage discharge blood to at 3 point 5 volt and this is here a cell of lfp battery versus capacity or time and you can see what this charge is very flat voltage plateau so this structure is very open so that you have high power because the lithium plus ions can migrate very fast inside this electrode it can be recharged quite fast the thermal stability is good but three main drawbacks first you lose about 300 millivolts as a medium cell voltage so that the energy density is about 30% less or even more than lithium ion batteries based on NMC materials only 120 watt hour per kilogram second when you hit the system iron here can is a partially soluble so at high temperature of these batteries are not really good and the third one is that LFP is very insulating material electrically insulating so what you need to make what we call a carbon coating here 2 nanometers of carbon coating to make it conductive that's another drawback but surely LFP batteries are lower voltage lower energy density fast recharge rate and a third one which is a technology from Nissan hanno is based on lithium manganese oxide al al I am n2o4 it's also an integration reaction of lithium plus into M n2o4 you see that the cell voltage 4.2 volt is a bit higher this is a discharge and recharge and for sure the main advantage of LM o is valo cost higher selves old-age higher power because this is very free D open structure where lithium can diffuse fast into materials but here again you have minus 20% of capacity versus NMC you are limited to 100 milli ampere Graham and when you have a temperature at which is fifty five sixty degrees you start to have a manganese dissolution by this mutation so this is a problem you have to manage the heat of a battery and now so it was state of the art and what about advanced lithium ion batteries so all these intercalation reactions we have described you have a limitation in capacity to 370 million per per gram for cupboard for instance the idea will be to move to higher capacity of anodes so for the analytic side what you can try to do is to make to use what we call early film allowing reactions which are 30 years old reactions very well known and you take for instance a metal and plus is missing here so we apologize for that and when you polarize this metal you can reduce lithium plus into the metal to form the lithium alloy and you can put up to four point for lithium per metal so what it means that now if you have looked to a specific capacity of a metal if you take carbon carbon one lithium one per day for six carbons means 372 million per hour per gram and you can see here silicium theoretically can reach four thousand million per per gram 12 times more why just because you can do the silicon plus four point five DM plus plus four point five electrons is alive four point four Si and this is a house standing capacitive anode just small problem you can see here metal alloy four hundred percent volume expansion when you do the lithium allowing reaction so you charge a battery you discharged battery you draw a battery discharged battery you do free cycles mechanically speaking these materials are not stable at all and this explains you why by this day there is huge huge huge research effort on silicon panasonic has launched this new second-generation battery but it's very tricky to to solve how to solve it this is an example taken from with Itachi the idea is to try to use nano structured silicon silicon anodes why just because in fact see a city solenoid just because in fact if you use nanostructured materials you can have void volume to buffer mechanical expansion between the particles and you have here strategies you start from porous carbon you do a CVD of silicon onto it a city's human to it sorry and then here you have this ten micron particle decorated with citizen you have here this is a muffle solution and this is a graphite here TEM image graphite layers you can see that this is graphite open 33 nanometer between the graphene layers and you have here more or less 15 nanometer sized silicon particle have a look cycle by DT is very good capacity 1600 milli ampere per gram you limit the number of lithium intercalated alloy divyam by 2 to 2.5 no more and when you have something very stable so this is an example of how to make a silicon-based anode you have plenty of other strategies like in formulation and recognized commercialization overseas in progress but this is a very very hot topic another key advance which is very recent is not yet under commercial this is discovery in 2007 by mike tack fred in us of what we call lithium rich phase NMC material remember you have Co six layers and lithium plus in between okay when you have n MC material means by the side for cobalt is shared between cobalt manganese and nickel so you may have one transition metal in this sides okay lithium rich phase are here on the side of a transition metal you put a lithium plus and then you have a lithium additionally film infrastructure okay so that's a way to increase the capacity but people who did VAD in 2007 they they did not understood how the how did it work and if you have if you take this structure this in fact nickel 2 manganese for cobalt 3 nickel 2 can be oxidized up to nickel plus 4 this one is maximum this one can be oxidized up to plus 4 so you can theoretically exchange 0.4 elec for one molecule and if you do a cycling with material you can see that on this charge this is a potential versus time at constant current you can exchange up to 0.9 electrons so there is a problem twice more capacitive and vertical based on Leon the oxidation state of metals why this has been solved very recently by Rama at a school you have here the cell voltages time or capacity whatever you want during charge is for a riffin young base material okay and what you see is the first plateau is the oxidation of ruthenium into ruthenium +5 okay you replace cobalt by ruthenium and here the second plateau is oxidation of oxygen and two peroxo spacy and this is completely a new parody because it shows that you can have first accumulated evidence of redox reaction on the metal and also a redox reaction on the oxygen it was the first time that it was understood last year and now it opens the way it pays the way for new active materials for positive electrode of lithium and batteries with higher capacity based on the redox not only on the metal but also on the oxygen group and this is fundamentally new and you can have a look back to materials which were previously disregarded like niobium oxide whatever you want so this is really interesting when see this is Rhian going it's a 18 months old what technology for the future because we did more or less current state-of-the-art advanced if you mind batteries what for 10 years oh sorry if you take the product table you have lithium which is very nice an old low potential lightweight and oxygen high potential low weight to Faraday's so you can combine and assembling a lithium battery what is the female battery very interesting this is at the negative electrode you oxidize lithium in the lithium plus at the positive electrode you reduce oxygen and 202 to - Barack silly okay theoretically 2.3 kilo watt hour per kilo five times the fuel main battery if you put this in electrical vehicle means the 1000 1500 500 kilometres autonomy realistically one kilowatt-hour eight hundred kilometer autonomy for electric car alright by de fumer very very nice four volt outstanding but problem first problem when you charge a cell here you go up to a four volt when you discharge the cell you go down to 2.5 volt there is a huge difference in the cell voltage because there are a lot of resistances it's very complicated second problem when you discharge a cell here when you reduce oxygen you don't go directly to to repair also Spacey you go through this intermediate which is super oxide ion super oxide is especi which is responsible for aging of human body this is a super oxidizing agent so as long as you form super oxide you are going to oxidize the electrolyte you are going to oxidize the carbon you are going to oxidize everything so the key problem to solve relief your my battery is to trap this super oxide specie which is a reaction intermediate formed during the discharge so as a result there are several issues that can be not have to be tackled to try to make Olivia main battery working instability of lithium metal because this is negative electrode of lithium vs electrolyte in polarization low kinetics for reaction precipitation of Li 2 O 2 so this is an insulator what is it yeah this is an insulator so it's not really not really good and cycle life is very poor because of a super oxide however last week so it was October 30th 2015 in science the group from Claire gray at Cambridge University in UK they have published a very interesting paper it does not solve everything well this is the beginning of the answer so they put okay what did they found you remember what I show you here the discharge and this is recharge huge polarization you see they use a graphene oxide as an active material and this is the discharge and this is the charge polarization is only 0.2 volt so they have solved a part of a problem how did they do well just bit science so they just use the redox mediator iodine and this iodine here during the charge you are going to form ivory - and this I free - is going then to oxidize lioh into water then you remove all repolarization let's say but this is a very interesting concept and a tricky idea that can be very interesting for virtually Fiamma but this does not solve the appearance of a super oxide ion so it solves a powerful problem but this is not the solution but this is really interesting next perspective sodium versus lithium where is it well lithium ion batteries why not sodium ion same materials intercalation alkaline same same process sodium carbonate is merged less expensive and lithium abundance 10 - 5 more sodium magnesium - drawbacks first potential of sodium 300 millivolt lower means that in fact a sodium and that we would discharge 300 millivolt love and if you mind you will lose 25% of energy second drawback the capacity you have one third of capacity because sodium is heavier than lithium sodium is 21 gram thermal lithium is 7 so you lose one-third two-third of the capacity never mind this is a very interesting alternative to lift your mind batteries a club or crossed of course you know you are going to lose energy but this can be very interesting for master age so I will come back on this point later on a last perspective this is here specific energy versus different technologies and this is to power with this Nissan Leaf vehicle so today we've currently human technology a leaf can do can have autonomy of 160 kilo meter if you move to a fuel if you mind take this is what I show you with for instance silicon as anode and lithium rich cafard you can you can think about reaching 250 kilometer okay future leaf your minds if you move to lift your mayor okay fine more than 600 kilometers autonomy but lithium air is really really tricky then the fume sulfur sounds really interesting form the 5,500 kilometers how does it work you take lithium metal as anode and sulfur here sulfur a scaffold so reduce sulfur into sulfides and then you end up with this reaction you form Li 2 s Rho CV is 2.4 volt quite low but it's very huge capacity so that energy density is very large and here the sulfur is not made solid sulfur it's a sulfur which is trapped into porous carbon and you have here a discharge plot and the charge plot battlefury because practically speaking you go through to move from this to this you go through all these reaction steps and you have eight five different steps and you have five different problem to solve why because you form spaces here sulfides you see here some of its sulfides are soluble so many other surfaces are insoluble insulators and then you have a lot of problem to tackle it and to deal with however one solution to try to solve issue is to again to confine the sulfur Interpol's common which has been done two years ago by a Canadian group in McGill University these are very good results and leave a sniffing surfer battery starts work today but more there is a recent paper here in 2014 that shows that if you take titanate titanate material you put sulfite lithium sulfite on top of it just by polarity you can really really really stack felicium sulfur on to the titanium and then you can block and trap the sulfur onto this kind of materials and you have a look here this is cycle number 100 cycles at 1,000 yen per gram which is quite outstanding for himself er and this is one way to solve the psychic ability of issue of lithium sulfur and really the femme surfer is very old-fashioned technology 50 years old but today major advances have been done and really we are very close to a commercialization of lithium sulfur to my opinion this is the next battery that will come into a market and just message my opinion again what ahead before lithium air systems also they are breaking news that you can see sometimes in newspapers in lamang journals in internet from very serious universities very outstanding work maybe a bit of a salt and this is an example of last April you'll Traverse rechargeable aluminum ion battery why is it very appealing and sexy the title lives on plus one electron for one lithium aluminium three plus three electrons for one aluminium so you can multiply by free the capacity and then energy density so this guy from Stanford University they said that they prepared succeed in preparing integrated battery based on the inter collation of aluminium I no one was able to make intercalation of aluminium ion which is very tricky however if you have a look back to a detail of a work first they use complexed aluminium ions you see there is only one minus charge there is only one charge the aluminium not free only one so very interest is a bit decreased and then they used as well a negative electrode which is aluminum foil and carbon form as a positive electrode to put materials so huge void volume so energy that volumetric energy density very low and when they use ionic liquids various different systems well it's it's promising definitely it's interesting concept but today if you compare these performance with lithium-ion battery this is ten times lower energy density for this battery so this is just a kind of over setting maybe I would say of a work by very efficient communication business office from Stanford but it's interesting there is something but this is definitely not the end of a lithium-ion battery and last there was also 18 months ago an announcement from our via technology 400 water per kilogram word recalls of lithium-ion battery 400 watt hour per kilogram terrific I mean more than two times or two times the energy density of lithium-ion batteries what what what's the trick in fact there is no trick they use silicon based anode fine this is something which is a in many labs and also they use Power Cells no aluminum case so the kg weight of a packaging is very light and second they use very very very thick Electro's millimeter thick electrodes so that you have in the same volume a lot of active material but since you use thick electrodes the power capability is very very very very low so this plot was certainly obtained at sea by Tennessee by 20 C by 50 discharged at very very low rate there is no power inside so there is no miracle okay so I will move to the second part of a talk which is about super caps and just have a look to what with time okay okay super capacitors again basic principles I would send me more applications because maybe super caps are less known when the batteries and I will give you also few words about micro pulse commands so same revenue plots you remember capacitors batteries we are going to focus on here what is in between the batteries and covers in ends and capacitors so super caps very high power much higher power from batteries lower energy density high energy density medium energy density high-power low-power so if you make a ratio between energy and power you have defined the definition of a time constant which is about 10 seconds 10 seconds here means that super caps are used the key application of super caps is to deliver power during 10 seconds 10 50 seconds and the interest of super capacitors unlike lithium-ion batteries is that you can discharge as fast as you charge the super cap the message is that they are complementary device Rises super so power battery for energy super caps more or less this is illusion bolt this is a sprinter 100 meters and batteries are a legacy - I used to be the world record in the marathon race so this is really a good good example so what's the trick for super caps how does the charge is stored in fact varies no redox reactions super caps they store the charge only by pure electrostatic mechanism when you polarize this is an electrode that you put into a sodium chloride sea wall if you polarize your electrode platinum electrode if you inject negative charges then what you are going to see is sodium ions who are going to migrate to your electrode and balance the charge created onto the metal surface so you polarize negativity you electrode by a charger and sodium ions balance a charge and you form here a capacitor okay the capacitance is the product of a dielectric constant of electrolyte because there is no vacuum this is electrolyte here multiplied by the surface of the electrode divided by D or delta which is approaching distance of the ions to the electrode surface D Delta is about few Armstrong so this is why you can go we can end up with 10 to 20 micro farad per square centimeter we are going to say 20 micro farad a square centimeter who cares who cares you're right if you use geometric current collectors but if you are able to use highly divided materials like porous carbons you take carbon you dig holes into the carbon and then you polarize the carbon and at the end if you take into account the walls of facebook porous carbon you can reach 15 and red square meter per gram 2000 square meter per gram so it means that if you just do a basic multiplication you can store in such very porous carbons more than 100 farad spectrum of carbon which is outstanding but there is a paper prior to pay which is the cell voltage in a pure dielectric cell voltage is limited by the electric breakdown of the dielectric voltage breakdown of the dielectric here this is the same it's limited by the electrochemical ectric Emeco the composition window electrical voltage window stability of the electrolyte in water you know that if you polarize beyond 1.2 volt water is going to be oxidized into oxygen reduced into hydrogen if you replace water with organic solvent propylene carbonate as tonight right then you can reach 2.5 volt for a single cell and within zero at 2.5 volt you just charge the charging supercups by iron absorption onto the carbon okay so those results this is a surface to reach the charge is very fast is easily available however in batteries the charge was stored inside the chemical bounds you reduce oxidized metals okay so that varies much let's charge in supercups but but very fastly available so very high power since the since this is not there is no charging to the bulk of the material since this is only surface storage you can charge and discharge at the same rate very fast this is also something very important when you have battery at the at the short state you have an oxy I mean you have for instance I don't know oxy an oxidant when you discharged battery you reduce oxidant you do reductant okay so it means that at the charge and discharge both electrode they change the composition lead oxide lead for instance for for latest battery so it means that you have always always a volume change between the charge state in the discharge state means that any battery will have a limited cycle life because of mechanical stress then this can be degraded by parasitic electrochemical reactions whatever you want but the basic principle of a batteries that recycle life is limited by volume change shiver cap surf a storage no volume change vertically cycle life is infinite practically speaking is more than one five million cycles so there is a completely different from batteries okay so I would leave few words about applications the first application was in a 380 this is for door emergency opening so in each of 16 doors you have a Vista Supercat model which is there and obviously this is for emergency opening so it did not work yet but it was demonstration that super cars were really safe to be implemented in this english jumbo jet so it was a niche market the real demonstration that super caps could do the job and safely so then super caps you can do also you can use super caps or energy recovery this is a tram you have in Paris t3 line and this is a collaboration between Alstom and brew solution from below and you have on the top of our of a roof you have here super caps models there I used to recover braking energy of another tram which is braking on the same line and we can be also used for pure electric drive for 100 meters to cross crossings and this is now in many many European capitals like Madrid you have in Berlin you have also in many towns in Barcelona well I don't remember you have 20 cities in Europe we were using this trampled by super caps so this is for mainly for energy recovery because of a fast recharge of super caps and then which is a key application hybrid active vehicles you have here the size you know that a hybrid like a vehicles is you combine thermal energy into electric engine and depending on the size of electric engine you are my cry breed my deliberate or full ibrid micro I breed is very small engine means that you do only few fewer key features for example stop and start and braking recovery energy recovery and you can see these two applications is about 6 kilowatt - to what our perfect for super caps and that reason why since 2012 for Citroen they equipped all vehicle's starter alternators with super caps so in fact you remove or you suppress of a batteries all the power all the peak power delivery which saves the lives of a battery and also a Mazda is doing that pursue did that with our technique and kalyug is doing this for dragons coming to the feel and blend well this is a very nice example for super caps and another example which is I would say is a bit at the border of super cheap a cap can do this is a still a bowl away this is what we call a brute run in fact it's a bus and and you have here super caps on the top of the roof of a bus there is no lithium-ion battery this is a pure super cap this is a pure electric drive by super cap why just because you have only one point five kilometer autonomy and in fact it means that you have a very close loop and you have stops each one kilometer and this bus can transport passengers between two stops at the stop during the passenger exchange very charged a super cap in 60 seconds one minute or even more so they take benefit from their very fast recharge and the infinite cycle life and this is something that they are doing if you take into account the psychic ability the cost which is about ten times more than lithium ion battery is going to be reduced very easily and then with the plant open last february and they are producing 50 bootrom is a year okay now let's move to the carbon which is the key part of the material of super caps I told you to sports carbon what do you do you go you start from a cadet shell which is a green green precursor and when you do a first carbonization and you end up with particles of about 5 to 10 micron and when you do what we call activation treatment what is an activation treatment you just it's a controlled oxidation of carbon into cos you and then you end up with pawns here and at the end you have you have this particle of about ten micron diameter and you have a porous network inside this particle and you create big pores micawber's bigger than 50 nanometers medium sized pores which are called missile polls between 2 and 15 nanometers and the smallest balls which are which are responsible for the highest of face area are called micro balls they are nano sized but they call it micro pores and then with specific surface area can be up to two thousand two thousand fifteen three thousand square meter per gram however so sorry so this is a real more or less that's it from a model it's not a real but this is what we imagine could be a real structure of a porous carbon however it's very difficult to control this process activation it's very difficult to control the pore size of a carbon you are producing so this is a probable universe is a pore width pore size in am shrank so you can see this is a very narrow pool size Goblin and you can see that the pore size goes between I would say 0.5 to 4 nanometer which is very large in fact and there was no idea there was no way in since 10 years there was no way to try to find a way to prepare carbons with very narrow pore size distribution and we end up with a method we I'm not going to detail about that but with a frame with a colleague were able to produce carbons with a control pore size below one nanometer and what we have found here we have found with our materials this is a carbon process this is normalized capacitance of carbons this is what we call what was available at a time that he taught you ok between 2 & 5 nanometers with activated carbons in fact people were thinking that you were able to absorb iron with scratching to add some ions by stacking ions on side of carbon per wall and you know because of a size of alien solvated iron side you need at a time to be between 2 & 5 nanometers to maximize the shock to minimize overall volume and people fought that be no.1 there was no way for ions to go inside pause video 1 nanometer because surveyed ions were bigger than 1 nanometer however when we did our cabins using a very specific technique we have shown that first pause blah world and the size was evaded ions were accessible to the ions and second there was huge capacitance increase in his Nana pores so it was evidence that first you need completely to rethink about units option into his columns second all those carbons people were producing were completely wrong they need to produce carbons with very small and narrow path size below one nanometer and then it was also a parody James you can separate people cabins but also from the intellectual point of view it was completely unexpected and we started to work on badging understanding of everything on that so just another example if you move from liquid electrolyte with solvent and salt you remove the solvent you just take what we call ionic liquids I need liquids there are solvent free electrolytes you take sodium chloride you eat that 860 degrees you have molten sodium chloride you can do the same with other materials but some of them are liquid at room temperature this is particular the case of EMI plus cation TFSI - anion so this is a liquid at room temperature there is no solvent no salvation shell and you can see the size is about 0.72 6 nanometer open 79 nanometer and when you study the capacity of our carbons in these LEDs in these ionic liquids with a carbon which has a pore size of 0.72 2 nanometer you have maximum capacitance and this was a very important message that here when you don't use any solvent you maximise the capacitance when the pore size is more or less equal to variance eyes so it was also a very new way of concept for preparing materials well I'm gonna skip that which is modeling and I'm gonna just make a summary about super caps so perspective for super this is to increase energy density which is given by half of half of the capacitance multiplied by square voltage and to try to increase energy density to 1015 water per kilogram so you can do it first by increasing capacitance this is why I show you to try to understand iron sides both sides whatever you want to try to design you carbons with tailor tailor made carbons within you as tiny properties but you can try to use also other materials which are going to mix redox reactions but only onto the surface of materials fast redox reaction materials like niobium oxide that we we prepared with colleagues from UCLA you can that's that's another way and you try to increase the cell voltage so there's a lot of things which are developing now with ionic liquids solvent free electrons because you are not limited by the solvent decomposition for the electrolyte with voltage window stability and also hybrid devices I will give you words maybe doing questions if I have questions about that which is called the lithium ion capacitor you mix you take a negative electrode of lithium ion battery graphite and a positive electrode of capacitor super capacitors so you can buy energy and power but that will end my talk about by giving few words about the French Network and batteries so this is initiative at with what was pushed by senior s in the French Ministry we have been created in 2011 so together with jean-marie Tarascon we we we tried to have we tried to develop basic science with moving this network on on batteries to improve knowledge and technology transfer from research to industry and to develop a French expertise in the field so this is a building 6000 square meter we are going to have anemia in December 2016 so we have three major pillars the first one is what we call academic research center we have 15 labs in France including in introduce obviously we are developing basic research on batteries any kind of batteries then we have technological transfer Center which is led by CA see a little deity in Erie's and EF trainers in Val and then we have industrial club so this is a true industry are missing but anyway so we have companies we are which are partner to the French Network and we are exchanging all together and the dream is to design new ideas new material to transfer these materials to the technological Transfer Center and to be produced by companies so that's the foop so we are working on five major fanatics first is advanced lithium ions second is capacitive storage super caps eco compatible storage organic materials for batteries green green batteries whatever you want ACV new chemistry is lithium sulfur sodium ion redox rosolie state batteries and smart materials were we couple batteries and photovoltaic properties we have cross-cutting reserve centers with safety safety platforms theory platform and a lot of in situ techniques and we have also something what we call pre transfer cell we have a hearing Nemea prototyping cell we are able to make some prototypes of batteries and this is a safety safety safety cell britain's first cell so i would like to give you three examples of what we did recently at a french level on batteries the first one advanced lithium ion you saw that this is a Redux mechanism that you might ask inoculation of hans discovered by playing not only on the cation oxidation state but also with oxygen oxidation state you can increase capacity of materials so that's really something which is in the next feature which is going to be very important and the key show to solve here is a stability cycle bility you can go up to 320 million per gram you can double the capacity on super caps in so what we need was to try to understand i am transferring nanopores and we did some institution mr spectra together with Gregory at Cambridge and you can see here what we need we took a cell we need some polarization at constant voltage here and we track the signal of anions and cations by flowing the fluorine and a phosphor signal and you have here during positive polarization the number of anions and the number of cations you put a rise positivity become one you can see that an is enter cations are living no more but when you go to the negative polarity when you polarize negativity of goblin cations are entering normal but anions here constant they don't leave so that's something which is quite difficult to understand but this is something which has been a check double check triple check and we have definitely a different storage mechanism between the positive polarization and negative polarization and this is something we have to understand deeper to try to understand how to improve again the capacity of storage in nanopores gallons and this is a key concern to address to design optimized structures and the last example is about moving from lithium and to sodium ion batteries so this is what we did was to create a sodium ion battery taskforce you remember why sodium the cost drawback 300 millivolt lower potential for sodium so that you have a 30% energy in City less but the cost is really here the main motivation so we started to work on this design a positive electrode made with n vpf this is a sodium vanadium phosphate flow Rhine okay negative electron of carbon of or antimony and this is done and doesn't mapache when you take antimony electrode this is alloying reaction you remember allowing reaction surprisingly in sodium it works very nicely you have here capacitive as a cycle number 600 million per gram 250 cycles very nice on the positive electrode we have designed a new material I mean a new structure of old-fashioned material and EPF it works this is the charge here the discharge each potential time it works very nicely and then together with a CA with a technical transfer we move from few grams per batch of synthesis of positive material but we did invalid two batches today we are we are preparing 500 gram batches per batch of NV PF and we were able at ca to make some electrodes and to prepare the first sodium iron prototypes in the 1865 650 prototype the first prototype of a world of sodium ion batteries and the performance were very interesting for first trials this is a chips this is 1 ampere our prototype this is milliampere per gram of positive electrode very stable cycle life very good power 80 water per kilogram means 20% less than LFP the human battery not nothing optimized very nice results and we took a lot of patents and we are really developing this technology which could be we very idea would be to try to create a French French PDA on sodium ion batteries well and this is all the colleagues from the fridge network and batteries and this is the end of my talk how I have not been too long and well I thank you all for your attention [Applause] [Music]

Channel: IRT Saint Exupéry

Views: 16,640

Rating: 4.8235292 out of 5

Keywords: energy storage, supercapacitors, electrochemical energy, batteries

Id: _WE_SPIjgvc

Length: 52min 37sec (3157 seconds)

Published: Wed Sep 06 2017