Category Chemistry/Nanotechnology

Step by step towards the complete shell: Formation of a metal cluster from the atomic constituents to the compound. Credit: Dehnen Group, Philipps-Universität Marburg

First the nucleus, then the shell: Researchers from Marburg and Karlsruhe have studied stepwise formation of metal clusters, smallest fractions of metals in molecular form. The shell gradually forms around the inner atom rather than by later inclusion of the central atom. Knowledge of all development steps may allow for customized optoelectronic and magnetic properties.

To specifically synthesize chemical compounds, mechanisms responsible for their formation have to be known. “Purely inorganic compounds are a black box in this respect,” Florian Weigend of KIT and Stefanie Dehnen of Philipps-Universität Marburg explain...

Polyhedral representation of the crystal structure of fluoride-phosphate of vanadium and potassium. The yellow denotes a three-dimensional channel system, which provides rapid transport of Li+ ions. Credit: Stanislav Fedotov

A cathode material for li-ion batteries with a very high charge rate – down to 90s – has been created, retaining more than 75% of an initial capacity. The discovery may stipulate the development of batteries where expensive lithium could be replaced with cheaper potassium.

Nowadays Li-ion batteries power a wide range of electronic devices: mobile phones, tablets, laptops. They became popular in 90s and subsequently ousted widespread nickel-metal hydride batteries. However, their capacity may drop when temperature falls below 0...

The new carbon-based material for sodium-ion batteries can be extracted from apples. Credit: KIT/HIU

A carbon-based active material produced from apple leftovers and a material of layered oxides might help reduce the costs of future energy storage systems. Both were found to have excellent electrochemical properties and stand for the environmentally compatible and sustainable use of resources. Sodium-ion batteries are not only far more powerful than nickel-metal hydride or lead acid accumulators, but also represent an alternative to lithium-ion technology, as the initial materials needed are highly abundant, accessible, and low cost. Hence, sodium-ion batteries are a very promising technology for stationary energy storage systems.

Schematic structure of the layered oxides produced...

Doped lithium titanate (LTO) nanoparticles could be incorporated into Li-ion batteries used in, for example, electric or hybrid automotive applications. Credit: Image courtesy of University of Eastern Finland

Lithium-ion batteries are a rapidly growing energy storage method due to their high energy density, especially in mobile applications such as personal electronics and electric cars. However, the materials currently used in Li-ion batteries are expensive, many of them, like lithium cobalt oxide (belonging to the EU Critical Raw Materials, CRMs), are difficult to handle and dispose of. Additionally, batteries using these materials have relatively short lifetimes.

New novel materials are being developed for next generation Li-ion batteries...