Whether for electric mobility or as a stationary storage for alternative energy: it is Still unclear which technology will prevail in the battery technology in the future. Although the undisputed market leader for many years, the Lithium-ion battery (LIB). But researchers are looking already for Alternatives. Your goal is a Post-Lithium Era is: to solve the problems of the current technology.
of Course an alternative, batteries of the future would have to meet all that is demanded today, but barely. As a automotive battery should allow a range of at least 500 kilometres in a matter of minutes to be charged, have a long service life, many charging cycles enduring, safe, secure, and sustainable – at a low cost.
This is a challenge. The International energy Agency predicts that the number of electric vehicles will increase by 2025 from the current 2 million to 70 million worldwide. The government of China will, by 2020, twelve percent of all cars in the country are driving electric, that alone would be more than 30 million E-vehicles. In addition, India, a number of States have announced in Europe and other countries, to want to be in the long term of gasoline and diesel engines disconnect. That this Revolution with Lithium-ion-batteries alone, is more than questionable.
Since the first Lithium-ion battery, which brought Sony in 1991, is a substantial part of the cathode of Lithium-cobalt oxide produced. This is a problem. “The cobalt oxide density lead to a high memory”, says Maximilian Fichtner. The chemist is the Deputy Director of the Helmholtz Institute Ulm (HIU). “But cobalt is obtained in large part by child labour, it is toxic and expensive, and it is getting more and more expensive.” Objective of the international battery research, a successor to the Lithium-technology without cobalt was. In this case, the HIU conducts research in cooperation with the Karlsruhe Institute of technology, the University of Ulm and centre for solar energy and hydrogen research Baden-Württemberg.
cobalt is priceless scarce
On the benefits of the LIB you want to resign, however reluctantly. “She is actually a great battery. Lithium ions are small, easily and quickly between the Anode and the cathode,” says Fichtner. The Lithium-ion technology has exhausted Fichtner however, according to their potential. In the last twenty years, the cobalt funding increased five-fold, the Element is also needed for the production of steel. If this continues, the cobalt in a few decades, to the priceless lack of the goods. The electric mobility should grow strong, should also the lithium to promote to increase to about ten times the present quantity. The Philipp adelhelm from the University of Jena is of concern. The chemist is working on both the optimization of the LIB as well as Alternatives. “Without a doubt, will soon be the reprocessing of used Lithium-ion batteries is important.”
At the same time, researchers are looking for materials for Post-Lithium technology. “They can be based on non-critical elements such as sodium, Magnesium, aluminum, or calcium.” Among several options, the sodium-ion battery is, apparently, flourished temporarily at the most. In principle, it is similar to the LIB, but with sodium instead of Lithium. The cathode requires no cobalt. “We call this a Drop-in technology”, explains Fichtner. For the change from Lithium to sodium, you need to change, therefore, technically, little. The first of these battery cells prior to serial maturity.
in Addition to being a sodium ion does not require a battery pack without cobalt, it forms a technically stable System with a high degree of efficiency. Furthermore, sodium as the raw material is not particularly sustainable. It is in table salt, in sea water, or in underground Salt domes. One drawback that remains, however: “We will achieve with sodium ions never the energy density of Lithium, because the sodium ions are simply bigger and heavier,” explains Maximilian Fichtner. For electric cars, sodium is not ideal for stationary energy storage from wind and solar power plants, or private homes but in the medium and long term is the better Option.
In an electric car could take over, however, elements such as Magnesium, the role of sodium in the Magnesium-sulfur batteries. According to some researchers, theoretically, the higher the memory, the alkaline earth metal is at least densities to be reached than Lithium. “Magnesium is a hot candidate, if we manage to solve a few more problems – more cycles, and better energy efficiency,” says Fichtner. For the raw material would be ensured. Magnesium there is in rough quantities, and sulphur is often simply stockpiled, for example in the desulphurisation plants.
Magnesium is not the only Alternative. Thus, U.S. chemists to the concepts, cobalt and Nickel in the Lithium works to replace batteries. “Alternative electrode types made of cheap and readily available metals such as iron and copper should be urgently developed” claim Konstiantyn Turcheniuk and employees from the Georgia Institute of Technology in the journal “Nature”. In order to eliminate the cobalt, keep the researchers so-called conversion materials, such as copper and iron fluorides, as well as silicon for the “best Alternative”. This would save the Lithium-ion is chemically and not merely, as at present in the LIB technology, physically in the electrodes sticking. “In such a conversion cathodes up to six times may be stored more Lithium-ion chemically as in standard cathode.” That sounds good, but does this technology works for now only in the laboratory.
peanut shells, corn cobs and Apples for the electrode
But back to the main candidate the memory of the future: the sodium ion battery (NIB). In order to increase their performance, thought of the Helmholtz researchers have a special feature that you would expect in a battery: the substances found in spider blood and organic waste. This is not a joke, but applied electro-chemistry. “Electrodes are made of organic and natural produce of substances has many advantages,” says Fichtner. “Flexible Design, good theoretical Storage density, ease of processing, safety, sustainability and low cost, actually a miracle material.”
Organic electrodes could be used in lithium batteries, in order to reduce the Cobalt content, but also in cobalt-free sodium batteries. You might want to reduce, so the scientists hope, the charging time in batteries of the future dramatically, the capacity increase, and yet over thousands of charging cycles, remain stable. A candidate for organic NIB electrodes in a ring-like molecule, the Porphyrin. In nature it is found in Chlorophyll, blood and Vitamin B12. In the variant of a copper-Porphyrin it is in the blue blood of crabs and spiders.
“We have modified biological copper-Porphyrin chemically and with a Trick stabilized,” says Fichtner. To achieve similar storage capacity as Lithium and sodium, in addition, several Thousand charge cycles. “The Performance is extraordinary. You can load the cell in a Minute.” This allows the application as a fast-charging battery for the stabilization of the power network. The only visible disadvantage is that The new cells fall off more.
bio-waste the other major Innovation of the HIU-researchers: Apples, corn cobs and peanut shells, which decomposes when exposed to extreme heat, dried, and crushed. The powder product contains predominantly carbon and can be on the negative terminal of the battery. “The peanut shells work so far, the best,” says Maximilian Fichtner.
certainly not short Of ideas for the researchers, anyway. However, chemists such as noble helm of the University in Jena, Germany warn against too much euphoria: For new batteries, there is a Wealth of ideas, but also a lot of hot air. “All too often, uncritical world records and immediate applications.” Scientists should, however, be as noble helmet says, “brave enough, and to shed light on disadvantages of new materials in equal measure.” Many of the published materials are “sophisticated structures” would not achieve the low cost of advanced Lithium-ion batteries for a long Jojobet time.
(Sunday newspaper)
Created: 09.12.2018, 15:07 PM
