Dr. Xueping Qin

Postdoctoral Research Fellow

The Hong Kong University of Science and Technology

Dr. Xueping Qin received her Bachelor in Materials Science and Engineering from Central South University (2014) and a Ph.D. degree in Department of Chemical and Biomolecular Engineering from the Hong Kong University of Science and Technology in August 2019. She is now a postdoctoral research fellow in the Hong Kong University of Science and Technology. Her research mainly focuses on theoretical studies in Li-ion batteries and fuel cells, using density functional theory simulations to investigate the interfacial decomposition reactions of electrolytes in Li-ion batteries and reaction mechanisms in electrocatalytic reactions including hydrogen evolution reactions, oxygen reduction reactions and CO2 reduction reactions. She has published 7 papers as the first author or equal contribution.

First-Principles Density Functional Theory Studies on Electrochemical Reactions

First-principles density functional theory (DFT) simulation has become a powerful tool to explore material properties and reaction mechanisms in electrochemical energy conversion and storage devices. In this study, DFT simulations were applied in understanding electrolyte decomposition mechanisms in lithium-ion batteries (LIBs) on both LiCoO2 (LCO) and LiNi1/3Co1/3Mn1/3O2 (NCM) layered cathode materials. It was found that the decomposition of ethylene carbonate (EC) was initiated by ring-opening reaction and followed by H-abstraction reaction on metal oxide surfaces. In another study, Li plating mechanism in Li metal-based batteries was elucidated by DFT simulations for the first time. The extreme reactivity of the Li metal induced a strongly inhomogeneous electron distribution upon deposition of a cation on the surface. DFT calculations were also used to explore electrocatalytic reactions including hydrogen evolution reaction (HER) and CO2 reduction reaction (CO2RR) on various advanced electrocatalysts. Pd3Ru alloy consisting of Ru clusters on catalyst surfaces showed excellent activity toward HER in alkaline solutions. Theoretical simulations demonstrated that Ru clusters could weaken the H binding energy and enhance the OH adsorption, thus reducing the reaction barrier of the rate-determining step. Fe, N co-doped carbon materials (Fe-N-C) showed excellent selectivity on CO during CO2RR. DFT simulations revealed that Fe sites were poisoned by strongly adsorbed *CO, which was consistent with the in situ infrared absorption spectroscopic results. The excellent CO2RR performance originated from Fe-N4 moieties embedded in defective nanoporous graphitic layers with balanced binding energies of *COOH and *CO intermediates.