Marie-Liesse Doublet : Conceptual vs. Computational Approaches to Energy Materials (IRSAMC, 14 janvier)


Marie-Liesse Doublet
ICGM, Montpellier

LIEU  : Salle de séminaire, bâtiment 3R1B4- Bat. IIIr1-B4, 3ème étage
DATE  : lundi 14 janvier, 14h

Abstract
Increasing the energy density of cathode materials is a central goal of the ongoing research in Li-ion batteries. This implies improving simultaneously the capacity and the potential of the materials used at the positive electrode of the electrochemical device. Today, the amplitude of the electrochemical potential of an electrode material is relatively well-controlled through an appropriate choice of the redox centre involved in the Li-driven electrochemical reactions. [1,2] Meanwhile, increasing the capacity of high-potential materials is more difficult to achieve without penalizing the material structural stability. So far, materials showing the highest energy densities are the Li-rich layered transition metal oxides for which a cumulative cationic and anionic redox activity has been demonstrated. [3-6] Nevertheless, the origin of extra-capacity in these systems has raised controversial debates in the literature with no real consensus about the directions to follow to overcome the structural instability that often comes along with the anionic process. [7-9] In this presentation, we use simple concepts of chemical bonding, band structure theory and topological tools of the electron density to address the fundamental question of high-energy-density of current batteries with the hope that a common language will help in clarifying the relationship between the material electronic structure, the potential, the (extra)-capacity and their consequence on the material structural stability. [10] This unified picture clearly highlights the trade-off that needs to be found between potential and capacity for the next generation of Li/Na-ion batteries.

References.

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