Seven Nobel Laureate was questioned whether \”super batteries\” is the Holy Grail or farce?
October 9, 2019, the Royal Swedish Academy of Sciences announced that it would grant John B. Goodenough and other three scientists the Nobel Prize in Chemistry in 2019, in recognition of their \”created a rechargeable world.\” Goodenoughcobalt oxide, lithium manganese oxide and lithium iron phosphate cathode material of the inventors, can be described as truly \”father of lithium.\” Now ripe old age he is still working in the front line of scientific research, hope for the world to make a super-battery electric vehicles and diesel locomotive match. In fact, as early as 2017 Goodenough team in Energy Environ. Sci. On dispatch announced the development of an energy density of conventional lithium battery is at least 3 times the solid-state batteries. And it is this breakthrough, so many scholars, people outside the industry doubt the reliability and authenticity of the results and theory. But Goodenough and coworkers Maria Helena Brag super-equipped for such a solid glass electrolyte battery (battery glass) with confidence, and its ongoing research. At the same time, Scania engineers MattLacey also continued to focus on research Goodenough team in this field, and on a personal blog (http://lacey.se/) discloses a battery of questions about this glass.
questioned from the beginning of 2017, when Goodenough laboratory announced a safe, inexpensive, fast charge, all solid, long-life battery technology, and the news has been strongly sought after technology media. Among them, responsible for carrying out this work was to Maria Helena Braga. Solid electrolyte glass concept originally proposed by her, its technology is in college Porto, Portugal, and colleagues have developed together. a question: Glass battery appears to violate the first law of thermodynamics Matt first started questioning the operation mechanism of the glass battery from the 2017 essay Ener.. Gy Environ Sci showed that metal lithium negative electrode, a solid electrolyte glass, a sulfur – C – glass composite positive electrode composed of a solid electrolyte cell capable of releasing 10 times higher than the theoretical capacity of the charge amount S (Li negative electrode theoretical capacity 90%). Goodenough team interpreted this result as long as the voltage remains above 2.34 V, the voltage on the sulfur redox centers determined cell, and electrons from the negative electrode reduces the electrolyte / cathode interface to the anode of a lithium Li + ; at 2.34 V or less, S 8 molecules are reduced to Li 2 S x (1≤x≤8) until the Li negative electrode is depleted. Matt believes battery-operated in this manner is without precedent. In such a cell the half reaction, Li metals in the negative electrode is oxidized: and re-deposited on the positive electrode: The two equations combined, equivalent to no chemical reaction occurs, the battery voltage is about 2.5V , the theoretical capacity of the battery is only determined by the lithium electrode, the theoretical energy density of this battery will be up to 8500 Wh / kg. Transformed into practical applications, the energy density can reach ten times the conventional lithium-ion battery (based on a rule of thumb theoretical energy density material / 4).
Key Since the challenge is that there is no chemical reaction, where the energy that ? from in this regard, in the Goodenough, to ComputerWorld in response: If the plating layer of lithium to the positive electrode current collector is sufficiently thin that it collector Fermi reaction may be reduced to make the Fermi collector near the Fermi energy, the lithium anode is higher than the Fermi energy plated onto the thin layer of lithium in the positive electrode current collector can. But this response did not untie doubt Matt\’s . Described herein should UPD, Matt monolayer that lithium atoms (a few nanometers thick) at a higher potential may be deposited on different substrates (2.5 V but the voltage is huge – at such a high under voltage, lithiumNot even any metal alloy). Even so, this effect may occur in up to a few monolayers, but still correspond to very small amounts of charge. When the lithium atoms deposited on the positive electrode current collector, negative electrode for lithium to be deposited on itself, it is deposited in the equilibrium voltage, Therefore both sides of the cell will not have the lithium chemical potential difference, naturally there is no voltage, this is clearly contrary to the results in Figure 2.
of the positive electrode deposited
Second question: rechargeable battery of?
EnergyEnviron. Sci. indicates voltage> 2.34 V, the battery can be charged and S are not restored. When the S content is positive 1.99 mg, the battery was discharged to 2.34 V, the amount of charge by the theoretical capacity of sulfur (about 1672 mAh g -1 ) of about 8.5 times (FIG. 2), where the battery can be estimated amount of 1.99 mg × 1672 mAh g -1 × 8.5 = 28.3 mAh. Energy Environ. Sci. also demonstrated cell may chargeability, a charge current of 40 mA / g, the charging time of 10 h, thereby calculating each of the battery charge / discharge cycles total charge passed was 1.99 mg × 40mA / g × 10 h = 0.796 mAh. Matt that This is only 2.8% of the reversible battery capacity, the battery did not show a deeper level in the charge / discharge state of how this works out . In this narrow window, the theoretical energy density of the battery is about 240 Wh / kg, then a rule of thumb, was 60 Wh / kg at the actual state, is much lower than the commercial lithium ion battery .
Question three: glass stability and purity of the electrolyte
EnergyEnviron Sci The electrolyte is a glass based on Li .. 3 crystal OCl amorphous material, the authors claim have been prepared by dopingAmorphous material having a higher conductivity and electrochemical stability window> 8 V in. Matt Paper but has noted (DOI: 10.1021 / cm4016222) calculated crystalline Li Properties of 3 OCl according to first principles, and is predicted to decompose Li 2 [123 above 2.55 V ] O 2 and LiCl: this reaction occurs with Energy Environ Sci in a similar voltage battery charging voltage, battery that Matt continuous overcharging possible. and oxidation electrolyte concerned. Also, by reviewing other related papers Goodenough team, Matt found electrolyte composition of each paper are given slightly different, and hardly any evidence to determine the true composition of the electrolyte glass . Preparation of the electrolyte is relatively simple glass, adding \”drops\” precursor in water, and then to evaporate at room temperature, ambient pressure, detected in the product of the Li 5 (OH) [123 ] 2 Cl 3 impurities, but Matt the precursor of LiOH ⋅ H 2 O oxide can condense into doubt at room temperature. And the possible side effects of the presence of water in the battery will be more complicated, Matt real reaction in the battery there is a big question, but did not get a response. Part
Ⅱ 2018 Nian 4 Yue, Goodenough and Braga, who published a title in the JACS
on as \”Nontraditional, Safe, High Voltage Rechargeable cells of Long CycleLife\” papers, Articles of the new system is based on the same glass cell electrolyte, after 23,000 cycles through a still capable of LED lights days [ 123]. Matt believes there is a big inconsistency in its electrochemical properties of the battery, there are also serious analysisFlaws and inconsistencies. In particular discussion of \”self-charging\” a, Matt misunderstanding that this stems from the nature of the electric double layer capacitor. question four: Why does the battery capacity will be increased?
In this JACS, the authors used the positive electrode is an electrode layer interposed –Li [Li x Ni
0.5 -y mn 1.5 -z ] O 4 -x-δ F x (LNMO). In order to make the positive electrode into close contact with the glass electrolyte, of the succinonitrile (SN) made of a waxy coating on the positive electrode side of a plasticizer, and an organic electrolytic solution added dropwise to a drop of the positive electrode and an electrolyte stick together. Since the presence of an organic electrolytic solution, Matt that will be described as an all-solid battery is completely wrong. Figure 4. Comparison of three half cell electrochemical performance of the positive electrode prepared in the same batch, (a, b) Li / electrolyte + Celgard / LNMO + C + PVDF; (c) Li / electrolyte + Celgard / SN + LNMO + C + PVDF; to increase the battery capacity as the number of cycles (dg) Li / Li-glass in paper / SN + LNMO + C + PVDF experimental observation
+ will diffuse to the surface Li negative electrode, is deposited as metal Li, the absence from the positive electrode Li + added to lead glass electrolyte negatively charged. The positive electrode side, away from the electronic LNMO particles, such LNMO positively charged particles, the anionic plasticizer SN accumulate in an EDLC particle surface of the positive electrode material is formed, and in the SN plasticizingAgent – electrolyte interface also glass because of their different charge, the formation of an EDLC, thereby pushing up the entire capacity of the battery. Matt that although this is reasonable, but the problem is present in the DL capacitance in a liquid electrolyte, and the positive electrode capacity and the intercalant is very much smaller than itself. Moreover supercapacitor using the activated carbon surface active high, but compared with the cell materials, their stored energy is still relatively small. Matt so that rely only on EDLC, it is difficult to make the battery more than 2 times the theoretical capacity. Matt that there are many possible side reactions in the battery contribute to charge storage, such as succinonitrile, the electrolytic solution was added wider voltage window or the like. Further, Because the battery active material is very low (0.1-0.25mg), side reactions leading electrolyte is entirely possible capacity of the battery, the decomposition of the electrolyte is entirely possible to produce a compound having redox activity, and can effectively store this charge size . Figure 5 a schematic view from the charge
question five: self-charging? When
2017, Goodenough in response to Bloomberg \”What is a self-charging\” interview, said: \” Braga this self-charging battery LED lights lit up for two years, it relies on the environment heat run . \”this caused Matt attention because there is no battery can not be known without any applied current to charge the heat extracted from the atmosphere. The author believes that
This is due to self-charging equilibrium Fermi level on the negative electrode / electrolyte interface, and fast movement between the arrival time of the electrolyte cations and the electrolyte interface electric dipole caused by the difference of the slow-moving. When the charge reaches the electric dipole, by plating electrolyte cations to the negative (i.e., self-charging), a negative charge is generated in the electrolyte, so that the Fermi level by a balance EDLC interface. Matt but that such an electric double layer capacitive effect – Fermi level calibration – occurs on both electrodes of each cell – but the charge stored in the battery is no net change, so certain \”self-charging\” does not exist . Part
Ⅲ As of March 2020, Goodenough and Braga, who had been published nearly ten articles on glass cell, Matt its just published in on Applied Physics Reviews \”Performance ofa ferroelectric glass electrolyte in a self- charging electrochemical cell withnegative capacitance and resistance \”is particularly interested in the article. Braga, who said they had developed a new cell which can charge itself, which will be a revolutionary breakthrough in energy storage. They
not only \”self-charging\”, but also charged with a semi-regular burst, authors attributed to ferroelectric liquid electrolyte glass. this work even for people familiar with the field of batteries is also difficult to understand , Matt thought this article there are still many doubts. questioned Six: electrolyte is almost certainly not the high performance of ferroelectric glass, but various salts of wet paste
Matt has been on such a glass electrolyte composition and structure of the doubt, and that is not a small amount of Ba substituted claims of Li Li 3 OCl glass. If so, it should be extremely sensitive to reaction with water, and must remain particularly dry, in order to achieve the stated performance authors, but the authors did not. Thus, material purity and dryness on doubtful from the outset. Researchers of the Technical University of Graz in Austria repeated the preparation of this material, and a strict and meticulous characterization work to determine its true composition and structure (DOI: 10.1021 / acs.chemmater.8b02568). As expected, their synthetic material contains a large amount of hydrogen (from water), is formed closer to Li
2 (OH) Cl substance. And they found that a compound begins to decompose on contact with air, formation of Li 2 CO 3 and key LiCl⋅xH 2 O (one compound capable of forming glass high electrical conductivity) and the like compounds. On this basis, the electrically conductive components of the electrolyte are glass LiCl⋅xH 2 O mixed with other impurities, not that they are doped with Ba Li 3 OCl. In addition to high conductivity, the presence of free chlorine ions and water, means that any lithium battery system, electrolyte are many unwanted side reactions. Moreover, This also makes the \”ferroelectric\” to explain the results of the paper with the electrolyte substantially is unacceptable, since the compounds in the electrolyte is not found in nature is a ferroelectric . question seven: Some record-breaking property due to fundamental miscalculation
dielectric constant this. papers and papers as before, pointed out there is a huge glass electrolyte dielectric constant, which are at least an order of magnitude than any other known material. Why so big? Yes, On miscalculated . This problem stems from the fact: no matter what this material is made of, it is not a pure dielectric, but ionic conductor. If a thin layer of dielectric or ionic conductor sandwiched between two electrodes, the resulting one capacitor. When the current through it, it will store or to release energy by a certain accumulated charge on the electrode surface. Ion conductor is a dielectric (which has a dipole), but they also have mobile charge (e.g., Li
+ ), they are independent of the dipole in a host material is free to move. This produces the phenomenon of an electric double layer capacitor, in this process, having a different surface level of the contact electrode and the electrolyte, and there is a need to balance the energy difference – the difference between the energy stored in an EDLC. Because of this EDLC increases the dielectric capacitor, by contrast, it is very large. This means that accurate measurement of ion conductor of the dielectric constant is very difficult, if not consider EDLC, just trying to be calculated from the total capacitance of the dielectric constant, it would be impractical to get a huge number, such as Braga et al calculated. Matt EDLC calculated after taking into account a dielectric constant of 1.7 × 10 7 , than paper 2 × 10 8 an order of magnitude lower . Figure 6 a schematic view of the dielectric constant is calculated
Negative Capacitance Since the ferroelectric that Matt spontaneous polarization properties of the body, when they switch from one polarization to another polarization direction, which is in an unstable state during the transition. At this time, the local electric field in the material with respect to an external electric field is negative, and the polarization curve of the system voltage becomes S-shaped, i.e. negative capacitance phenomenon. However, the total capacitance of the system is still positive, otherwise it will violate the laws of thermodynamics. When this material is in the negative area of the capacitor, it is unstable and will tend to settle in one form or another in a very short time, so this is not self-charging, or from the circulation [123 ].
[summary] Despite many questions, but still not enough evidence to show who is wrong, no altar of science, the authority does not necessarily represent the truth. Science needs criticism, the truth is often more debates. The time will give the fairest answer! Original link: Part I: http: //lacey.se/2017/03/29/on-the-skepticism-surrounding-the-goodenough-battery/ second part: http: //lacey.se/2018/07/ 05 / glass-battery-part-2 / part III: http: //lacey.se/2020/03/13/braga-goodenough-glass-battery-part-iii/ References:
MH braga, NSGrundish, AJ Murchison, JB Goodenough. Alternative strategy for a safe rechargeable battery. Energy Environ. Sci. 2017, 10 (1), 331-336, DOI:.. 10.1039 / C6EE02888H
Maria Helena Braga, Chandrasekar M Subramaniyam, Andrew J. Murchison, John B. Goodenough Nontraditional, Safe, High Voltage Rechargeable Cells of Long Cycle Life J. Am Chem Soc 2018, 140 (20), 6343-6352, DOI:….. 10.1021 / jacs.8b02322