{"title":"Suppression of magnetism and Seebeck effect in Na0.875CoO2 induced by SbCo dopants","authors":"M. H. N. Assadi, Paolo Mele, Marco Fronzi","doi":"10.1007/s40243-020-0165-9","DOIUrl":null,"url":null,"abstract":"<p>We examined the electronic property of Sb-doped Na<sub>0.785</sub>CoO<sub>2</sub> using density functional calculations based on GGA+<i>U</i> formalism. We demonstrated that Sb dopants were the most stable when replacing Co ions within the complex Na<sub>0.875</sub>CoO<sub>2</sub> lattice structure. We also showed that the Sb<sub>Co</sub> dopants adopted the?+?5 oxidation state introducing two electrons into the host Na<sub>0.875</sub>CoO<sub>2</sub> compound. The newly introduced electrons recombined with holes that were borne on Co<sup>4+</sup> sites that had been created by sodium vacancies. The elimination of Co<sup>4+</sup> species, in turn, rendered Na<sub>0.875</sub>(Co<sub>0.9375</sub>Sb<sub>0.0625</sub>)O<sub>2</sub> non-magnetic and diminished the compound’s thermoelectric effect. Furthermore, the Sb<sub>Co</sub> dopants tended to aggregate with the Na vacancies keeping a minimum distance. The conclusions drawn here can be generalised to other highly oxidised dopants in Na<sub><i>x</i></sub>CoO<sub>2</sub> that replace a Co.</p>","PeriodicalId":692,"journal":{"name":"Materials for Renewable and Sustainable Energy","volume":null,"pages":null},"PeriodicalIF":3.6000,"publicationDate":"2020-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1007/s40243-020-0165-9","citationCount":"4","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Materials for Renewable and Sustainable Energy","FirstCategoryId":"1085","ListUrlMain":"https://link.springer.com/article/10.1007/s40243-020-0165-9","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"MATERIALS SCIENCE, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 4
Abstract
We examined the electronic property of Sb-doped Na0.785CoO2 using density functional calculations based on GGA+U formalism. We demonstrated that Sb dopants were the most stable when replacing Co ions within the complex Na0.875CoO2 lattice structure. We also showed that the SbCo dopants adopted the?+?5 oxidation state introducing two electrons into the host Na0.875CoO2 compound. The newly introduced electrons recombined with holes that were borne on Co4+ sites that had been created by sodium vacancies. The elimination of Co4+ species, in turn, rendered Na0.875(Co0.9375Sb0.0625)O2 non-magnetic and diminished the compound’s thermoelectric effect. Furthermore, the SbCo dopants tended to aggregate with the Na vacancies keeping a minimum distance. The conclusions drawn here can be generalised to other highly oxidised dopants in NaxCoO2 that replace a Co.
期刊介绍:
Energy is the single most valuable resource for human activity and the basis for all human progress. Materials play a key role in enabling technologies that can offer promising solutions to achieve renewable and sustainable energy pathways for the future.
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