Cover Picture: Three‐Dimensional Microstructural Characterization of Lithium Manganese Oxide with Atom Probe Tomography (Energy Technol. 12/2016)

Abstract

An inGeenious Programm:The GEENI programme (https://www.tu‐braunschweig.de/forschung/zentren/nff/geeni) in Lower Saxony in Germany on energy storage devices and electric mobility was set up to identify potential solutions how electric mobility can be best achieved without using fossil fuels. The challenges addressed start at the development of the electrode material and end at the test of full cells regarding their application in electric vehicles. More specifically, the challenge being addressed is to significantly increase the understanding of the processes in lithium batteries at various size scales through new, or enhanced, preparation, analytical, and numerical methods. This Special Issue provides an overview of the research jointly conducted at five Universities in Lower Saxony and the MEET Battery Research Center at the University of Münster with the aim to expand the current knowledge base relating to transport processes (ion, electron, and heat flow), material mechanical stresses, and manufacturing processes to substantially improve battery systems. The cover art illustration shows lithium manganese oxide particles, a commonly used electrode material. One of the long‐standing challenges is the microstructural characterization of the electrode material itself and identifying the influence of the different microstructures on the (de)intercalation of Li ions. Using atom probe tomography, it was possible to identify different phases, phase segragation as well as a lamellar microstructure and their effect on charging/discharging. Using this information, it should be possible to further improve electrode materials. You can read more in the Full Paper by Johannes Maier et al. at the University of Göttingen on page 1565 in Issue 12, 2016 (DOI: 10.1002/ente.201600210).

A Hybrid Density Functional Theory Benchmark Study on Lithium Manganese Oxides

“…A miscibility gap exists between the cubic (x = 1) and tetragonal (x = 2) spinel structure. [11] If the average Li content is higher than x = 1, the tetragonal phase with x = 2 will form and both phases coexist in the range 1 < x < 2. Detailed insights into the structure of Li x Mn 2 O 4 have been gained in various experiments, e. g. X-ray diffraction, transmission electron microscopy and atom probe tomography.…”

“…Detailed insights into the structure of Li x Mn 2 O 4 have been gained in various experiments, e. g. X-ray diffraction, transmission electron microscopy and atom probe tomography. [11,12] Theoretical studies are able to provide complementary information, for example, about the underlying atomistic processes of the phase transitions or about the Li diffusion pathways. However, the underlying electronic structure of Li x Mn 2 O 4 is very complex due to the large number of energetically close electronic and magnetic states.…”