{"title":"石榴石型Mg3Fe2Si3O12的原子尺度研究:缺陷化学、扩散和掺杂性能","authors":"Navaratnarajah Kuganathan , Alexander Chroneos","doi":"10.1016/j.powera.2020.100016","DOIUrl":null,"url":null,"abstract":"<div><p>Materials with low cost, environmentally benign, high structural stability and high Mg content are of considerable interest for the construction of rechargeable Mg-ion batteries. In the present study, atomistic simulations are used to provide insights into defect and diffusion properties of garnet type Mg<sub>3</sub>Fe<sub>2</sub>Si<sub>3</sub>O<sub>12</sub>. Calculations reveal that the Mg–Fe anti-site defect cluster (0.44 eV/defect) is the lowest energy intrinsic defect process. Three dimensional Mg-ion migration pathway with the activation energy of 2.19 eV suggests that Mg-ion diffusion in this material is slow. Favourable isovalent dopants are found to be Mn<sup>2+</sup>, Ga<sup>3+</sup> and Ge<sup>4+</sup> on the Mg, Fe and Si sites respectively. While the formation of Mg interstitials required for the capacity is facilitated by Al doping on the Si site, Mg vacancies needed for the vacancy assisted Mg-ion diffusion are enhanced by Ge doping on the Fe site. The electronic structures of favourable dopants are calculated and discussed using density functional theory.</p></div>","PeriodicalId":34318,"journal":{"name":"Journal of Power Sources Advances","volume":null,"pages":null},"PeriodicalIF":5.4000,"publicationDate":"2020-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.powera.2020.100016","citationCount":"2","resultStr":"{\"title\":\"Atomic-scale studies of garnet-type Mg3Fe2Si3O12: Defect chemistry, diffusion and dopant properties\",\"authors\":\"Navaratnarajah Kuganathan , Alexander Chroneos\",\"doi\":\"10.1016/j.powera.2020.100016\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>Materials with low cost, environmentally benign, high structural stability and high Mg content are of considerable interest for the construction of rechargeable Mg-ion batteries. In the present study, atomistic simulations are used to provide insights into defect and diffusion properties of garnet type Mg<sub>3</sub>Fe<sub>2</sub>Si<sub>3</sub>O<sub>12</sub>. Calculations reveal that the Mg–Fe anti-site defect cluster (0.44 eV/defect) is the lowest energy intrinsic defect process. Three dimensional Mg-ion migration pathway with the activation energy of 2.19 eV suggests that Mg-ion diffusion in this material is slow. Favourable isovalent dopants are found to be Mn<sup>2+</sup>, Ga<sup>3+</sup> and Ge<sup>4+</sup> on the Mg, Fe and Si sites respectively. While the formation of Mg interstitials required for the capacity is facilitated by Al doping on the Si site, Mg vacancies needed for the vacancy assisted Mg-ion diffusion are enhanced by Ge doping on the Fe site. The electronic structures of favourable dopants are calculated and discussed using density functional theory.</p></div>\",\"PeriodicalId\":34318,\"journal\":{\"name\":\"Journal of Power Sources Advances\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":5.4000,\"publicationDate\":\"2020-06-01\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://sci-hub-pdf.com/10.1016/j.powera.2020.100016\",\"citationCount\":\"2\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Power Sources Advances\",\"FirstCategoryId\":\"1085\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S2666248520300160\",\"RegionNum\":0,\"RegionCategory\":null,\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q2\",\"JCRName\":\"CHEMISTRY, PHYSICAL\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Power Sources Advances","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S2666248520300160","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, PHYSICAL","Score":null,"Total":0}
Atomic-scale studies of garnet-type Mg3Fe2Si3O12: Defect chemistry, diffusion and dopant properties
Materials with low cost, environmentally benign, high structural stability and high Mg content are of considerable interest for the construction of rechargeable Mg-ion batteries. In the present study, atomistic simulations are used to provide insights into defect and diffusion properties of garnet type Mg3Fe2Si3O12. Calculations reveal that the Mg–Fe anti-site defect cluster (0.44 eV/defect) is the lowest energy intrinsic defect process. Three dimensional Mg-ion migration pathway with the activation energy of 2.19 eV suggests that Mg-ion diffusion in this material is slow. Favourable isovalent dopants are found to be Mn2+, Ga3+ and Ge4+ on the Mg, Fe and Si sites respectively. While the formation of Mg interstitials required for the capacity is facilitated by Al doping on the Si site, Mg vacancies needed for the vacancy assisted Mg-ion diffusion are enhanced by Ge doping on the Fe site. The electronic structures of favourable dopants are calculated and discussed using density functional theory.