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ASM family fun day in Fælledparken; June 2020

BIG-MAP: Battery Interface Genome - Materials Acceleration Platform

The ASM section trying out curling.

Battery 2030+: New large-scale and long-term research initiative in EU 

Prof. Tejs Vegge gives the keynote lecture at the Science Award Electrochemistry and Science Dialogue 2019 hosted by BASF and Volkswagen. In picture: Prof. Tejs Vegge, Prof. Doron Aurbach, Prof. Linda Nazar, Prof. Jürgen Janek, Nobel Laureate Prof. Stanley Whittingham, Prof. Martin Winter.

AiMade – A new initiative on Autonomous Materials Discovery at DTU Energy

Contact Head of Section

Tejs Vegge
Professor, Head of Section
DTU Energy
+45 45 25 82 01

Contact Section Secretary

Karina Ulvskov Frederiksen
Section Secretary (Secretariat)
DTU Energy
+45 45 25 82 02

Research focus

The scientific focus in Section for Atomic Scale Materials Modelling (ASM) is centered on computational design and characterization of materials for energy conversion and storage, based on a detailed atomic-scale understanding of their structure and kinetics. An essential aspect of our work is the development and application of novel computational approaches, which are linked closely to experimental in situ structural and electrochemical characterization.

The two main research areas in ASM are Next-generation battery materials and Electrocatalystic reactions and materials, but the section has several other activities, including Solid-state storage of gas-phase energy carriers, Solar cells and photocatalysis, and Resistive switching memories. Common for the different research areas is a shared computational framework based on Computational screening and prediction of composition/structure and Ionic and electronic transport mechanisms.

Modulating Charge-Carrier Dynamics in Mn-Doped All-Inorganic Halide Perovskite Quantum Dots through the Doping-Induced Deep Trap States

 

Meng et al.
J. Phys. Chem. Lett. 2020, 11, 3705−3711

You can read the paper here.

 

We have systematically studied the effect of transition metal Mn2+ doping in the photo-physics of CsPbCl3 quantum dots (QDs). Through DFT calculations, we demonstrated a change of defect states in the internal of QDs, namely, the most possible defects shift from shallow PbCs electron traps to deep Cl interstitials (Cli) hole traps after Mn2+ doping. The investigation of the charge carrier dynamics via complementary TA and TRPL spectroscopies reveals the competition instead of mediation between exciton-dopant energy transfer and the hole trapping that occurs at early times after photoexcitation (< 100 ps). Such competition rationalizes the non-monotonic evolution of photoluminescence quantum yield (PLQY) with the doping level (i.e. PLQY first increases and then decreases with the increase of Mn2+ doping). Furthermore, because the energy transfer to Mn dopant mainly competes with the holes trapping, it is vital to passivate the holes traps during doping process to maximize the Mn2+ emission, for instance, by dual-doping. Meanwhile, the surface traps exist in QDs among the different Mn doping concentrations, which means surface treatment should arise attention in QDs preparation whether doped or not. Hence, this work provides a general model that can be used as a reference to optimize the future design of such perovskite.

Operando identification of site-dependent water oxidation activity on ruthenium dioxide single-crystal surfaces


Rao et al. 

Nature Catalysis, May 11, 2020 (DOI: 10.1038/s41929-020-0457-6)


 

You can read the paper here.

Here, we employed surface X-ray scattering coupled with DFT and surface-enhanced infrared absorption spectroscopy to examine OER on RuO2. At 1.5 VRHE, our results suggest that there is an –OO group on the RuCUS site of the (100) and (110) surfaces, but adsorbed oxygen on the RuCUS site of (101). DFT results indicate that the removal of –OO from the RuCUS site, which is stabilized by a hydrogen bond to a neighbouring –OH (–OO–H), could be the rate-determining step for (100) and (110), where its reduced binding on (100) increased the activity. A further reduction in binding energy on the RuCUS site of (101) resulted in a different rate-determining step (–O + H2O – (H+ + e) → –OO–H) and decreased activity. Our study provides molecular details on the active sites, and the influence of their local coordination environment on activity.

Facet-Dependent Electrocatalytic Water Splitting Reaction on CeO2: A DFT+U Study

Tiantian Wu, Núria López, Tejs Vegge, Heine Anton Hansen J. Catal. 2020, 388, 1-10

You can read the paper here
Ceria has attracted considerable interest for the high-temperature electrocatalytic water splitting reaction (WSR) in solid oxide electrolysis cells (SOECs). We found that the formation of reaction intermediates such as oxygen vacancies, hydroxyls and vacancy-hydroxyl mixed phases on CeO2(100) is much more stable than that on CeO2(110) and CeO2(111). The higher stability of hydroxyls on CeO2(100) inhibits hydroxyl decomposition into H2, as compared to the reaction on the (110) and (111) facets, leading to the WSR on CeO2(110) and CeO2(111) 10~100 times faster than the reaction on CeO2(100) at temperature (T) < 950 K.

 

The role of an interface in stabilizing reaction intermediates for hydrogen evolution in aprotic electrolytes

Ivano E. Castelli, Milena Zorko, Thomas M. Østergaard, Pedro Martins, Pietro P. Lopes, Byron K. Antonopoulos, Filippo Maglia, Nenad M. Markovic, Dusan Strmcnik and Jan Rossmeisl, Chem. Sci. 11, 3914 (2020).

You can read the paper here.

We combine idealized experiments with realistic quantum mechanical simulations of an interface to investigate electro-reduction reactions of HF, water and methanesulfonic acid (MSA) on the single crystal (111) facets of Au, Pt, Ir and Cu in different organic aprotic electrolytes. We find that the measured potential of the electrochemical response correlates with the work function of the electrode surfaces and that the work function determines the potential for Li+adsorption. In addition, the overpotential of the reaction is related to stabilizing the active structure of the interface, thus facilitating the reaction rather than providing the reaction energy.

Autonomous intelligent agents for accelerated materials discovery

Joseph H. Montoya, Kirsten T. Winther, Raul A. Flores, Thomas Bligaard, Jens S. Hummelshøj and Muratahan Aykol, Chem. Sci., 2020,11, 8517-8532

You can read the paper here
We present an end-to-end computational system for autonomous materials discovery. The system aims for cost-effective optimization in large, high-dimensional search spaces of materials by adopting a sequential, agent-based approach to deciding which experiments/calculations to carry out. In choosing next experiments, agents can make use of past knowledge, surrogate models, logic, thermodynamic or other physical constructs, heuristic rules, and different exploration–exploitation strategies. In a sample set of 16 campaigns covering a range of binary and ternary chemistries including metal oxides, phosphides, sulfides and alloys, this autonomous platform found 383 new stable or nearly stable materials with no intervention by the researchers.
Computational Design of Ductile Magnesium Alloy Anodes for Magnesium Batteries

Smobin Vincent, Jin Hyun Chang, and Juan María García Lastra.
Batteries & Supercaps (2020).

You can read the paper here
The brittleness of Mg makes it extremely difficult to produce thin foils for practical battery applications. Alloying with small amount of dopants can improve the ductility of Mg. We performed a computational screening of dopants that can alloy with magnesium and use as an anode in magnesium batteries. Three properties were evaluated for this screening: ductility improvement, stability of the alloy and propensity of dopant to reside in bulk to avoid electrochemical reactions. We considered 34 dopants and identified 12 dopants that are suitable for magnesium battery applications.