New directions in high temperature dielectrics: unlocking performance of doped tungsten bronze oxides through mechanistic understanding
Lead Research Organisation:
University of Sheffield
Department Name: Materials Science and Engineering
Abstract
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Organisations
People |
ORCID iD |
| Derek Sinclair (Principal Investigator) |
Publications
Hooper T
(2024)
Structural, dielectric, and conduction behaviour of A-site deficient Sr x Na 1-2 x NbO 3 ceramics
in Journal of Materials Chemistry C
Hooper T
(2024)
Structural and dielectric properties of CaSnO3-doped Sr2.1Na0.8Nb5O15 ceramics
in Journal of the European Ceramic Society
| Description | The dielectric properties of the primary material of interest in this grant (Sr2NaNb5O15, a Tetragonal Tungsten Bronze, TTB) are suitable for high temperature ceramics capacitors but unfortunately the material is metastable and the properties degrade over time at the upper operating temperature of 250 C. This metastability is linked to metal vacancies in this TTB material and we have been trying various chemical doping strategies (eg Ba and Ca for Na and Ti and Sn for Nb) to overcome the metastability. This work is having some success with the stability issues but, at this stage, the dielectric properties are not as good as the base material. In the last year our doping work has confirmed some improvement on the stability of the SNN solid solution but they are not thermodynamically stable. |
| Exploitation Route | This work highlights that TTB materials remain as good potential candidates as future dielectric materials but further understanding of their defect chemistry and thermodynamic are required. This is a broad class of materials that is of interest to the solid state community so the fundamental findings of our work will be informative to this community in future designing of TTBs as functional materials. |
| Sectors | Aerospace Defence and Marine Digital/Communication/Information Technologies (including Software) Electronics Energy Transport |