Prof. Yinwei Li [Jiangsu Normal University, China]

Title: Computational Design of High-Energy Density Materials at High Pressure

Time: 10:00 - 11:00 AM, Friday, August 4, 2017

Place: Conference room 410, HPSTAR (Shanghai)

Host: Lin Wang

Abstract

Polymeric nitrogen stabilized by compressing pure molecular nitrogen cannot be recovered to ambient conditions, precluding their practical applicability as high-energy density materials (HEDM). In this talk, I will show our two-recent works about the prediction of HEDMs at high pressure. The first work is about the prediction of a new HEDM with a unconventional stoichiometry B3N5, in which the transition pressure from triple N≡N bond to single N-N bond was lowered to 15 GPa, much less than that (>110 GPa) observed in pure nitrogen. Another work is about the formation of a new form of pure polymeric nitrogen (t-N) via He-N compounds at high pressures. We have predicted a thermodynamically stable compound HeN4, which adopts a structure consisting a polymeric channel-like sp3nitrogen framework filled with linear helium atoms above 95 GPa. The nitrogen framework can be preserved to ambient pressure after the removal of He atoms, forming t-N that is dynamically and mechanically stable at ambient pressure.

Biography of the Speaker:





Dr. Yinwei Li received his PhD degree in condensed matter physics from Jilin University in 2011, and then went to Jiangsu normal university as an associate professor. In 2014, he spent one year in University of Saskatchewan as a visiting scholar. His research interests mainly focus on computational design of new materials at high pressure, including high-temperature super conductors and high-energy density materials. He has published 45 papers in journals such as Nature, PRL, PNAS, PRB, etc., which have been cited about 1200 times. His H-index is 20 according to Google scholar. His prediction that H2S transforms into a super conductor with Tc of 80 K at high pressure has been verified by a subsequent experiment, leading to a record Tc of up to 203 K in compressed H2S.His work on H2S has been selected as one of the “2015’s Most Read Papers” and “2011-2015’s Most Cited Papers Published by Chinese” by the Journal of Chemical Physics.