Project C05

C05 - Controlling electron-driven chemistry by intercalation The main goal of this project is to control the multi-step charge transfer during the OER by tailoring material properties and surface microstructure of the spinel LixMn2O4. This widely used battery electrode material allows facile change of its composition, which we have used in collaboration with theoretical approaches to gain unexpected insights into the role of crystal and electronic structure on catalytic activity. In the third phase of the project, we will move to in-operando TEM and XAS experiments to gain direct information about the crystal and electronic structure of the active catalytic interface.

Figure. Combining quantitative electrochemistry, high-resolution spectroscopy and imaging with the simulations performed in project C03 will reveal the mechanisms controlling the oxygen evolution reaction (OER) at the surface of LiMn₂O₄.

The Cover Feature illustrates the interplay between the activity for the oxygen evolution reaction and the battery charge state of LiMn2O4 when used as a catalyst. The electrocatalyst remains in the discharged battery state at pH 14, whereas a charged battery state is observed as manganese oxidizes at lower pH values, which leads to catalyst deactivation. More information can be found in the Article by M. Baumung et al. in ChemPhysChem on page 2981 in Issue 22, 2019.

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 segregation 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. in the Journal Energy Technology on page 1565 in Issue 12, 2016 (DOI: 10.1002/ente.201600210).