Na+ Migration Mediated Phase Transitions Induced by Electric Field in the Framework Structured Tungsten Bronze.
J Phys Chem Lett
; 14(13): 3152-3159, 2023 Apr 06.
Article
em En
| MEDLINE
| ID: mdl-36961327
ABSTRACT
Framework structured tungsten bronzes serve as promising candidates for electrode materials in sodium-ion batteries (SIBs). However, the tungsten bronze framework structure changes drastically as mediated by the sodium ion concentration at high temperatures. While the three-dimensional ion channels facilitate fast ion storage and transport capabilities, the structural instability induced by Na+ migration is a big concern regarding the battery performance and safety, which unfortunately remains elusive. Here, we show the real-time experimental evidence of the phase transitions in framework structured Na0.36WO3.14 (triclinic phase) by applying different external voltages. The Na+-rich (Na0.48WO3, tetragonal phase) or -deficient (NaxWO3, x < 0.36, hexagonal phase) phase nucleates under the positive or negative bias, respectively. Combined with the theoretical calculations, the atomistic phase transition mechanisms associated with the Na+ migration are directly uncovered. Our work sheds light on the phase instability in sodium tungsten bronzes and paves the way for designing advanced SIBs with high-stability.
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01-internacional
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MEDLINE
Idioma:
En
Ano de publicação:
2023
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Article