Disordered Versus Ordered Niobates as Electrode Materials for Rechargeable Batteries by Professor Nicola Pinna

NTU MSE Seminar Hosted by Professor Lee Pooi See

Abstract

A well-ordered structure with high crystallinity is crucial in various applications, particularly in electrode materials for batteries. The dimensionality and connectivity of the interstitial sites, determined by the crystal structure, inherently influence alkali ions diffusion kinetics. Niobium-based oxides structures are built by the assembly of ReO3-type blocks of specific sizes with metal sites having well defined positions within the crystalline structure. Structural disorder generally disrupts the regular pathways for ion and electron transport, leading to a lower overall conductivity. Here, we report a new anomalous disordered niobium tungsten oxide structure that significantly enhances the Li-ion storage performance compared to the ordered phase. The disordered tetragonal phase consists of corner-shared NbO6 octahedra blocks of varied sizes, including [5x4], [4x4], and [4x3], with a disordered arrangement of the tungsten tetrahedra at the corners of the blocks, together with strong distortion of the WO4 tetrahedra. This structural arrangement is found to be extremely robust during lithiation/delithiation, with a homeostatic local structure evolution during cycling, as determined by operando X-ray diffraction and X-ray absorption spectroscopy. This study highlights the benefits of introducing disorder into niobium tungsten oxide shear structures, through the establishment of clear structure-performance correlations, offering valuable guidelines for designing materials with targeted properties.

Biography


Professor Nicola Pinna
Department of Chemistry
Humboldt University of Berlin

Nicola Pinna received his Ph.D. in physical chemistry from the Université Pierre et Marie Curie (Paris) in 2001. He has since worked at the Fritz Haber Institute of the Max Planck Society (Berlin), the Max Planck Institute of Colloids and Interfaces (Potsdam), the Martin Luther University of Halle-Wittenberg, the University of Aveiro (Portugal), and the Seoul National University (Korea). In July 2012 he joined the Department of Chemistry of the Humboldt University of Berlin as professor of inorganic chemistry. From July 2016 to April 2021, he was also head of the Department. In 2021 he co-founded BC Berlin Catalysts GmbH. His research activity focuses on the development of novel materials for energy and environmental applications.