The worldwide developments of electric vehicles, as well as large-scale or grid-scale energy storage to compensate the intermittent nature of renewable energy generation has generated a surge of interest in battery technology. Understanding the factors controlling battery capacity and, critically, their degradation mechanisms to ensure long-term, sustainable and safe operation requires detailed knowledge of their microstructure and chemistry, and their evolution under operating conditions, on the nanoscale.
Atom probe tomography (APT) provides compositional mapping of materials in three-dimensions with sub-nanometre resolution, and is poised to play a key role in battery research. However, APT is underpinned by an intense electric-field that can drive lithium migration, and many battery materials are reactive oxides, requiring careful handling and sample transfer. Here, we report on the analysis of both anode and cathode materials, and show that electric-field driven migration can be suppressed by using shielding by embedding powder particles in a metallic matrix or by using a thin conducting surface layer. We demonstrate that the challenges inherent to the APT analysis of battery materials are solvable and the approach will lead to atomic-scale understanding of battery materials in near-future.
Fig. (a) 3D atom map of the Li4Ti5O12. Cyan, pink, and dark green dots represent reconstructed O, Li, and Ti atoms, respectively. Scale bar is 20 nm. (b) 1D compositional profile along the measurement direction. A black dash-line displays the nominal Li atomic composition. (c) Bright field high resolution TEM images of LTO particles. Scale bars are (left) 50 and (right) 10 nm. (d) 3D atom map of LTO particle embedded in Ni. Scale bar is 50 nm. Green dots represent reconstructed Ni matrix atoms. Inset image is the corresponding backscattered SEM image of LTO particles APT specimen (scale bar = 200 nm). (e)&(f) Extracted nanoparticle regions in the atom map and (g)&(h) corresponding atomic compositional profiles along the cylindrical region of interests (ϕ5 nm).
Fig. (a) 3D atom map of the Li4Ti5O12. Cyan, pink, and dark green dots represent reconstructed O, Li, and Ti atoms, respectively. Scale bar is 20 nm. (b) 1D compositional profile along the measurement direction. A black dash-line displays the nominal Li atomic composition. (c) Bright field high resolution TEM images of LTO particles. Scale bars are (left) 50 and (right) 10 nm. (d) 3D atom map of LTO particle embedded in Ni. Scale bar is 50 nm. Green dots represent reconstructed Ni matrix atoms. Inset image is the corresponding backscattered SEM image of LTO particles APT specimen (scale bar = 200 nm). (e)&(f) Extracted nanoparticle regions in the atom map and (g)&(h) corresponding atomic compositional profiles along the cylindrical region of interests (ϕ5 nm).
The segregation of impurity elements to grain boundaries largely affects interfacial properties and is a key parameter in understanding grain boundary (GB) embrittlement. Furthermore, segregation mechanisms strongly depend on the underlying atomic structure of GBs and the type of alloying element. Here, we utilize aberration-corrected scanning…
In this project, we aim to synthetize novel ZrCu thin film metallic glasses (TFMGs) with controlled composition and nanostructure, investigating the relationship with the mechanical behavior and focusing on the nanometre scale deformation mechanisms. Moreover, we aim to study the mechanical properties of films with complex architectures such as…
This project is a joint project of the De Magnete group and the Atom Probe Tomography group, and was initiated by MPIE’s participation in the CRC TR 270 HOMMAGE. We also benefit from additional collaborations with the “Machine-learning based data extraction from APT” project and the Defect Chemistry and Spectroscopy group.
The exploration of high dimensional composition alloy spaces, where five or more alloying elements are added at near equal concentration, triggered the development of so-called high entropy (HEAs) or compositionally complex alloys (CCAs). This new design approach opened vast phase and composition spaces for the design of new materials with advanced…
Thermoelectrics have attracted increasing attention as a sustainable and flexible source of electricity able to meet a wide range of power requirements. Their application is wide as they could be used as main source of electricity as in satellites or used to increase efficiency of thermal processes in industries or cars or any other application…
This project aims to correlate the localised electrical properties of ceramic materials and the defects present within their microstructure. A systematic approach has been developed to create crack-free deformation in oxides through nanoindentation, while the localised defects are probed in-situ SEM to study the electronic properties. A coupling…
Scandium-containing aluminium alloys are currently attracting interest as candidates for high-performance aerospace structural materials due to their outstanding combination of strength, ductility and corrosion resistance. Strengthening is achieved by precipitation of Al3Sc-particles upon ageing heat treatment.
Defects at interfaces strongly impact the properties and performance of functional materials. In functional nanostructures, they become particularly important due to the large surface to volume ratio.
In this project, we aim to design novel NiCoCr-based medium entropy alloys (MEAs) and further enhance their mechanical properties by tuning the multiscale heterogeneous composite structures. This is being achieved by alloying of varying elements in the NiCoCr matrix and appropriate thermal-mechanical processing.
