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!
Category: 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!
Structure-Property-Composition Relations in β-SiAlON:Eu2+ Phosphor
Our work on “Elucidating Structure–Composition–Property Relationships of the β-SiAlON:Eu2+ Phosphor” has been published in Chemistry of Materials. Using first-principles calculations, we identified and confirmed various chemical rules for Si−Al, O−N, and Eu activator ordering in β-SiAlON, one of the most promising narrow-band green phosphors for high-power light-emitting diodes and liquid crystal display backlighting with wide color gamut. Through the construction of energetically favorable models based on these chemical rules, we studied the effect of oxygen content and Eu2+ activator concentrations on the local EuN9 activator environment, and its impact on important photoluminescence properties such as emission peak position (using the band gap as a proxy), bandwidth, and thermal quenching resistance. Based on these insights, we discuss potential strategies for further composition optimization of β-SiAlON.
Thermodynamic scale of inorganic crystalline metastability
Prof Ong is a co-author on a recent article in Science Advances on the thermodynamic scale of inorganic crystalline metastability. This article uses the Materials Project, its API and pymatgen to perform a large-scale data-mining study of the thermodynamic scale of metastability for 29,902 observed inorganic crystalline phases. Press release is available on EurekAlert.
Room-Temperature All-solid-state Na-ion Batteries with Cl-doped Na3PS4
In collaboration with the Laboratory of Energy Storage and Conversion (LESC), we have developed a room-temperature all-solid-state rechargeable sodium-ion battery utilizing a novel Cl-doped Na3PS4 superionic conductor. The Cl-doped tetragonal Na3PS4 solid electrolyte exhibits room-temperature Na+ conductivity exceeding 1 mS/cm, and an all-solid-state TiS2/t-Na3−xPS4−xClx/Na cell utilizing this solid electrolyte can be cycled at room-temperature at a rate of C/10 with a capacity of about 80 mAh/g over 10 cycles. We show that this excellent electrochemical performance is not only due to the high Na+ conductivity of the solid electrolyte, but also due to the effect that “salting” Na3PS4 has on the formation of an electronically insulating, ionically conducting solid electrolyte interphase. This work is published in Scientific Reports. The co-first authors are Iek-Heng Chu (MAVRL), Christopher S. Kompella (LESC) and Han Nguyen (LESC), and the corresponding authors are Professors Shirley Meng and Shyue Ping Ong.
Materials Virtual Lab Retreat 2016
The Materials Virtual Lab held its first ever retreat today. We had a great day strategizing future research directions followed by a BBQ at La Jolla Shores. We officially welcome Chi Chen, Hui Zheng, and Zhuonan Lin to the group, and congratulate Richard Tran on transiting to a graduate student!
Data-driven Methods for the Study and Design of Alkali Superionic Conductors
Our article on “Data-driven First Principles Methods for the Study and Design of Alkali Superionic Conductors” has been published in Chemistry of Materials as part of an invited Methods and Protocols special topic. In this work, we provide a detailed exposition of the first principles techniques that can be used to design alkali superionic conductors, a topic of high current interest. Accompanying this article is a repository of well-documented Jupyter notebooks that allows any researcher to easily reproduce the analysis and apply the same techniques to other materials. The article is available online and the notebooks are available at the following Github repo.
Crystalium released
We have published the world’s largest database of surface energies and Wulff shapes, dubbed Crystalium. A collaborative effort between the Materials Virtual Lab and the Materials Project, this new open-source database can help researchers design new materials for technologies in which surfaces and interfaces play an important role, such as fuel cells, catalytic converters in cars, computer microchips, nanomaterials and solid-state batteries. You can read more about it in the UCSD press release on EurekAlert! This work is published in Scientific Data as an open-access article, and Richard Tran, one of our undergraduate volunteers, is the first author.
Zhi Deng passed his Senate Exam
Congrats to Zhi Deng, one of MAVRL’s founding members, on passing his Senate Exam!
Sodium-Rich Anti-Perovskite Solid Electrolytes
In this work published in the Journal of the Electrochemical Society, we studied the effect of cold-pressing and spark-plasma sintering (SPS) processing on the Na3OBr sodium-rich anti-perovskite solid electrolytes was studied. SPS was found to reduce the interfacial impedance by 3 orders of magnitude. The much lower conductivity of Na3OBr compared to the lithium analogue is attributed to the significantly higher defect formation energies. This work is led by the Laboratory of Energy Storage and Conversion of Prof Shirley Meng. Zhi Deng and Prof Ong are co-authors.