Wednesday, 21 June 11:00am – 12:00pm

This seminar will be delivered in Chemistry Lecture Theatre 4 and Online (Zoom) Please email chemistry.researchsupport@sydney.edu.au for zoom link and password.

Speaker: Prof Mesfin Kebede, University of South Africa

Host: Dr Kaye Kang

Title: Strategies to improve the electrochemical performance of electrode materials for lithium-ion battery

Abstract: The manganese-based cathode materials such as LiMn₂O₄ (LMO) cathode materials, and high-voltage LiNi_0.5Mn_1.5O_4-δ (LMNO) spinel cathode materials were synthesized and used for lithium-ion batteries (LIBs). The structural and electrochemical properties of the cathodes were characterized by XRD, XPS, CV and charge/discharge voltage profile analysis.

The cathode materials suffer from the capacity loss which is caused by Jahn–Teller distortion and slow dissolution of manganese in the electrolyte.

SnO₂ emerged as a promising anode material due to its low cost, safety, and high theoretical capacity of 782 mAh g⁻¹ as compared to commercial anode graphite which has a capacity of only 342 mAh g^-1. However, the Sn-based anode faces challenges as it experiences large volume changes (~250%or larger) during charge and discharge cycles that causes rapid capacity fading and poor cyclability, which limits its practical use as an anode material.

We have adopted different strategies to suppress the capacity fading of electrode materials. For the cathode materials the effect of microwave on the electrochemical performance have been studied. In the case of Sn-based anode, the improved electrochemical performance achieved by nano-structuring and carbon composite.

In this presentation, we will cover the strategies used to stabilize the electrochemical performance of selected Mn-based cathodes, as well as Sn-based anodes.

Bio: Dr Mesfin Kebede obtained his PhD in Metallurgical Engineering from Inha University, South Korea. And, both his MSc and BSc in Physics from Addis Ababa University, Ethiopia. He currently holds a position of Professor at Institute for Nanotechnology and Water Sustainability at University of South Africa (UNISA), South Africa. Prior joining UNISA, he worked as a Principal Researcher at Energy Centre of Council for Scientific and Industrial Research (CSIR), South Africa. In his prior career, he also worked as Assistant Professor in the Department of Applied Physics and Materials Science at Hawassa University, Ethiopia. He has been supervising Masters and PhD students, training and mentoring postdocs and emerging researchers on the field of electrode materials for coin cell and pouch cell fabrication.

His current research mainly focuses on the development and characterization of electrode materials for energy storage and fabrication of coin cell and pouch cell for full cells. Improving the electrochemical performance of electrode materials for energy storage systems such as lithium-ion batteries, sodium-ion batteries, and supercapacitors. He has published more than 60 ISI-Accredited International Journals, 11 book chapters, and edited 2 books with h-index of 19. He presented his works as invited speaker on several international conferences.

Google scholar link: https://scholar.google.com/citations?user=xp90BUQAAAAJ&hl=en&oi=ao