Presentation Title: Tuning Niobium-Based Electrodes for Safer, Faster Batteries

Abstract:

Batteries with higher energy density, faster charging, and improved safety are critical for applications ranging from electric vehicles to portable electronics. Achieving fast charging requires electrode materials that combine high-rate capability with structural stability. This presentation highlights how the composition and structure of niobium oxide–based materials govern their electrochemical properties, offering guidelines for knowledge-driven design. Niobium oxides with Wadsley–Roth shear structures enable ultrafast lithium storage using micron-scale particles. In operando Raman spectroscopy, combined with DFT calculations, reveals lithium adsorption sites, electronic structure, and transport pathways in these materials. Oxygen-deficient Nb₂₅O₆₂_–δ exhibits lower charge-transfer resistance, faster ion diffusion, and greater stability than stoichiometric H-Nb₂O₅. Mixed-phase electrodes (H-Nb₂O₅/M-Nb₂O₅) further enhance performance: edge-sharing [NbO₆] polyhedra mitigate volume expansion, while phase coexistence provides continuous Li-ion pathways. An entropy-tuned niobium oxide (ETNO) anode achieves exceptional high-rate capability (~170 mAh g⁻¹ at 20 A g⁻¹) and retains 79% capacity after 9,000 cycles under extreme fast-charging conditions. Experimental and computational analyses show that entropy tuning stabilizes phase evolution, accelerates Li-ion diffusion, narrows the energy bandgap, and reduces volume change during cycling. Finally, Nb₁.₆₀Ti₀.₃₂W₀.₀₈O₅_–δ (NTWO) demonstrates excellent performance in all-solid-state batteries, maintaining 80% of its capacity after 5,000 cycles at 45 mA cm⁻² and 60 °C.

Meilin Liu is the Hightower Chair and Regents’ Professor at Georgia Tech. He received his M.S. and Ph.D. from the University of California, Berkeley. His research focuses on the design, fabrication, in situ/operando characterization, and multi-scale simulation of materials for energy storage and conversion, with the aim of enabling the rational design of materials and structures with unique functionalities for chemical and energy transformations. He is a Fellow of the American Ceramic Society, the Electrochemical Society, the International Association of Advanced Materials, and the European Academy of Sciences.