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Conocimientos sobre el mecanismo de inserción de protones en el electrodo de hidrato de óxido de tungsteno hexagonal
Heng Jiang1, Jessica J Hong1, Xianyong Wu1
1Department of Chemistry , Oregon State University , Corvallis , Oregon 97331-4003 , United States.
Journal of the American Chemical Society
|September 6, 2018
Resumen
Los electrodos hexagonales de hidrato de óxido de tungsteno (WO3·0.6H2O) incorporan agua de celosía y se someten a un proceso de inserción de protones en tres etapas. Este material demuestra una excelente vida útil y un prometedor rendimiento electroquímico.
Área de la Ciencia:
- La electroquímica
- Ciencias de los materiales
- Química inorgánica
Sus antecedentes:
- El hidrato de óxido de tungsteno hexagonal (WO3·0.6H2O) es un material de electrodo prometedor para aplicaciones de almacenamiento de energía.
- Comprender el transporte de iones y la evolución estructural es crucial para optimizar su rendimiento.
Objetivo del estudio:
- Para investigar el comportamiento del agua en celosía durante la inserción y extracción de protones en WO3·0.6H2O.
- Para aclarar el mecanismo de múltiples etapas de la inserción de protones.
- Para correlacionar los cambios estructurales con el ciclo electroquímico.
Principales métodos:
- Se utilizó el microequilibrio electroquímico de cristal de cuarzo (EQCM) para controlar los cambios de masa durante el ciclo.
- Se empleó la difracción de rayos X ex situ (XRD) para analizar las modificaciones estructurales.
- Se realizó un ciclo electroquímico para evaluar el rendimiento y la estabilidad.
Principales resultados:
- WO3·0.6H2O incorpora agua en celosía al sumergirse y durante el ciclo inicial.
- La inserción de protones ocurre en tres etapas distintas que incluyen la expulsión de agua de la red, la inserción de protones desnudos y la inserción de iones de hidrónio.
- La protonación induce cambios estructurales anisotrópicos, incluida la contracción del eje c y la expansión del plano ab.
- El material presenta una larga vida útil (>20 000 ciclos) con buena capacidad y capacidad de velocidad.
Conclusiones:
- El estudio revela una compleja interacción entre el agua de la red y el transporte de protones en WO3·0.6H2O.
- La dinámica estructural observada es clave para la estabilidad y el rendimiento electroquímico del material.
- WO3·0.6H2O es un material de electrodo robusto con un potencial significativo para el almacenamiento de energía electroquímica.
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