Author: FirstCoder

Publications

Effect of transition metal mixing in Layered P2 Oxides

Our work on “Effects of Transition-Metal Mixing on Na Ordering and Kinetics in Layered P2 Oxides” has just been published in Physical Review Applied. In this work by Chen Zheng and other co-authors, we systematically investigate the effects of transition-metal (TM) mixing on Na ordering and kinetics in the NaxCo1−yMnyO2 model system using DFT calculations. We show that the TM composition at the Na(1) (face-sharing) site has a strong influence on the Na site energies, which in turn impacts the kinetics of Na diffusion towards the end of the charge. By employing a site-percolation model, we establish theoretical upper and lower bounds for TM concentrations based on their effect on Na(1) site energies, providing a framework to rationally tune mixed-TM compositions for optimal Na diffusion.

News

Plenary Talk at 57th Sanibel Symposium

Professor Ong recently gave a plenary talk on “Creating It from Bit – Designing Materials by Integrating Quantum Mechanics, Informatics and Computer Science” at the 57th Sanibel Symposium held on St Simon’s Island in Georgia, USA. The slides of this talk at available on SlideShare. In this talk, he discussed two emerging trends that holds the promise to continue to push the envelope in computational design of materials. The first trend is the development of robust software and data frameworks for the automatic generation, storage and analysis of materials data sets. The second is the advent of reliable central materials data repositories, such as the Materials Project, which provides the research community with efficient access to large quantities of property information that can be mined for trends or new materials. The talk showed how we have leveraged on these new tools to accelerate discovery and design in energy and structural materials as well as our efforts in contributing back to the community through further tool or data development, and provide perspectives on future challenges in high-throughput computational materials design.

matgenb

matgenb – Getting data from the Materials Project

The Materials Virtual Lab has started matgenb, a new public repository to share example notebooks that demonstrate the utilization of open-source codes for the study of materials science. We frequently get requests (from students, postdocs, collaborators, or just general users) for example codes that demonstrate various capabilities in the open-source software we maintain and contribute to, such as the Materials Project software stack comprising pymatgen, custodian, and Fireworks. This repo is a start at building a more sustainable path towards sharing of code examples. The first example notebook has been posted on Getting data from the Materials Project.

Publications

Divalent-doped NASICON with high Na+ conductivity

Our work on “Divalent-doped Na3Zr2Si2PO12 Natrium Superionic Conductor: Improving the ionic conductivity via simultaneously optimizing the phase and chemistry of the primary and secondary phases” has just been published in the Journal of Power Sources. In this work co-first-authored by Mojitaba Samiee (Luo group) and Balachandran Radhakrishnan (Ong group), we show that divalent dopants with low solubility in NASICON lead to the formation of a conducting secondary phase, thereby improving the grain boundary conductivity compared to undoped NASICON. Concurrently, the introduction of divalent dopants is accompanied by a change in the Si/ P ratio in the primary NASICON bulk phase, transforming monoclinic NASICON to rhombohedral NASICON. NASICON chemistries with significantly improved and optimized total ionic conductivity of 2.7 mS/cm have been synthesized. This work suggests a new general direction to improve the ionic conductivity of solid electrolytes via simultaneously optimizing the primary bulk phase and the microstructure (including grain boundary segregation and secondary phases).

Publications

Goodbye to Bala

This week, we say goodbye to our very first alumni, Bala. We wish Bala all the best in his new post at NASA, and look forward to his future discoveries and success as a researcher!

News

Editor for Computational Materials Science

Professor Ong has been appointed to the Editorial Board of Computational Materials Science. The goal of Computational Materials Science is to report on results that provide new insights into, or significantly expand our understanding of, the properties of materials or phenomena associated with their design, synthesis, processing, characterization, and utilization. All aspects of modern materials modeling are of interest, including quantum chemical methods, density functional theory (DFT), semi-empirical and classical approaches, statistical mechanics, atomic-scale simulations, mesoscale modeling, and phase-field techniques.

Publications

New Li3Y(PS4)2 and Li5PS4Cl2 Superionic Conductors

Zhuoying’s first author paper on “Li3Y(PS4)2 and Li5PS4Cl2, New Lithium Superionic Conductors Predicted from Silver Thiophosphates using Efficiently Tiered Ab Initio Molecular Dynamics Simulations” has just been published in Chemistry of Materials (Special Issue on High-Throughput Functional Materials Discovery). In this work, we propose two new lithium superionic conductors, Li3Y(PS4)2 and Li5PS4Cl2, that are predicted to have excellent ionic conductivity and potentially better stability at the interfaces compared to current state-of-the-art superionic conductors. We welcome experimental researchers to attempt synthesis of these compounds and validation of our predictions!

Announcements

2016 year-end message by Prof Ong

2016 is coming to a close. Before some of you leave for the holidays, I would like to wish you all a Merry Christmas. This year, I have decided to start a new tradition – the year-end message. It has been a great year for the Materials Virtual Lab. We have come a long way since our founding a little over three years ago, and I believe we have now firmly established ourselves as one of the up-and-coming computational materials research groups in the world. We will end 2016 on a high note with a little over 20 publications in highly respected journals. Funding is at a very healthy level for a group of our age, and we are now a dynamic family of three postdoctoral associates, ten graduate students and three undergraduates. Two of our earliest members (Zhi and Paul) have completed their Senate Exams, and another two (Chen, Zhenbin and Zhuoying) have completed their Literature Review Exams. We welcomed three new group members (Chi, Hui and Zhuonan), and one new-old group member (Richard) in Fall 2016. We will also soon say goodbye to Bala, who has found an excellent opportunity in NASA. We wish him all the best […]