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Desorden catiónico y mecanismo de inserción de litio de las fases de corte cristalográfico de Wadsley-Roth a partir
Can P Koçer1, Kent J Griffith2,3, Clare P Grey3
1Theory of Condensed Matter, Cavendish Laboratory , University of Cambridge , J. J. Thomson Avenue , Cambridge CB3 0HE , U.K.
Journal of the American Chemical Society
|August 27, 2019
Resumen
Las fases de Wadsley-Roth son prometedoras para las baterías de iones de litio. El modelado computacional revela cómo la colocación de tungsteno y los mecanismos de inserción de litio impactan las propiedades estructurales y electrónicas, mejorando el rendimiento de la batería.
Área de la Ciencia:
- Ciencias de los materiales
- Química computacional
- La electroquímica
Sus antecedentes:
- Las fases de corte cristalográfico de Wadsley-Roth son materiales prometedores para los electrodos de las baterías de iones de litio.
- Sus estructuras complejas desafían el modelado computacional y la comprensión de las propiedades.
Objetivo del estudio:
- Investigar las fases de corte del óxido de niobio-tungsteno (Nb12WO33, Nb14W3O44, Nb16W5O55).
- Descubra los principios del desorden catiónico, la inserción de litio y la estructura electrónica.
- Avanzar en el conocimiento para mejorar el diseño del electrodo de la batería.
Principales métodos:
- Se utiliza un enfoque basado en la enumeración.
- Utilizó los primeros cálculos de la teoría de la densidad-funcional.
Principales resultados:
- El tungsteno ocupa preferentemente sitios específicos, lo que influye en la estructura local.
- La inserción de litio sigue un mecanismo de tres pasos con la evolución de la red anisotrópica.
- Los cambios estructurales amortiguan la expansión del volumen, y los electrones localizados se convierten en metálicos al litiarse.
Conclusiones:
- Principios establecidos que rigen el trastorno catiónico y la inserción de litio en estas fases de corte.
- Evolución estructural local y de largo alcance vinculada a la expansión del volumen de amortiguación.
- Demostró que la evolución estructural y electrónica combinada beneficia el rendimiento de la batería.
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