The 15th Global Conference on Materials Science and Engineering (CMSE 2026)

Abstract: Lithium–sulfur (Li–S) batteries are promising next-generation energy storage systems due to their high theoretical energy density, yet their practical application is hindered by sluggish sulfur redox kinetics, severe polysulfide shuttling, and interfacial instability. This talk presents a unified framework that advances from material design to fundamental reaction physics. We first show that intrinsic catalytic activity is governed by bulk electronic structure. Transition-metal doping in ZnSe tunes orbital hybridization and enables control of sulfur redox kinetics. This concept is extended through defect–dopant coupling in MoS₂, where inner-layer doping stabilizes vacancies and creates electronically active sites with enhanced charge transfer. We then demonstrate that catalytic performance is also limited by reaction pathway constraints. Dual-doped MnO₂ enables bidirectional catalysis, accelerating both Li₂S formation and decomposition. However, single-site systems face intrinsic trade-offs between adsorption and conversion. To overcome this, a dual-terminal binding strategy spatially decouples polysulfide trapping and catalytic conversion, enabling simultaneous shuttle suppression and fast kinetics. At the atomic level, diatomic catalysts introduce cooperative interactions between active sites, enabling coupled electronic and spin effects beyond single-site limitations. Finally, we identify the fundamental origin of the rate-limiting step. The Li₂S₂ → Li₂S conversion is governed by spin-state transitions rather than purely thermodynamic barriers. Machine learning further reveals that spin density strongly correlates with reaction energetics. This work establishes spin-dependent reaction pathways as a universal design principle for high-performance Li–S batteries.
Keywords: Lithium-sulfur batteries, Spin-state engineering, Electronic structure modulation, Electrocatalysis, Reaction kinetics

Acknowledgements: This work was supported by the Science and Technology Development Fund, Macau SAR (File no. 0022/2023/RIB1), University of Macau (File no. MYRG-GRG2024-00166-IAPME and MYRG-GRG2025-00136-IAPME), the Science and Technology Innovation Committee of Shenzhen Municipality (SGCX20250526152800001), Guangdong Basic and Applied Basic Research Foundation 2026A1515012355 and the High-Performance Computing Cluster (HPCC) of Information and Communication Technology Office (ICTO) at University of Macau.

Biography: Kwun Nam Hui is an Associate Professor at the Institute of Applied Physics and Materials Engineering, University of Macau. He received his PhD in Electrical and Electronic Engineering from University of Hong Kong in 2009. His research focuses on advanced electrode and catalytic materials for energy storage and conversion, including lithium–sulfur, sodium-ion, potassium-ion, and aluminum-ion batteries, as well as supercapacitors and electrocatalysis (ORR, OER, HER, CO₂RR). His group integrates nanostructure design and computational methods (DFT, molecular dynamics) to enhance charge transfer and uncover reaction mechanisms. Dr. Hui has published over 300 SCI-indexed papers in leading journals such as Nature Communications, Advanced Materials, and JACS, with an h-index of 72 and over 17,000 citations. He has been recognized among the World’s Top 2% Scientists since 2021, is a Fellow of the Royal Society of Chemistry.