Sakata Gurmesa Gamachis, Teshome Tamiru, Ermias Benti Natei, Ayalneh Tiruye Girum, Datta Ayan, Setarge Mekonnen Yedilfana, Amente Geffe Chernet
Department of Physics, College of Natural and Computational Sciences, Addis Ababa University, P. O. Box 1176, Addis Ababa, Ethiopia.
Department of Physics, College of Natural and Computational Sciences, Addis Ababa University, P. O. Box 318, Mettu, Ethiopia.
ChemistryOpen. 2022 Jun;11(6):e202100289. doi: 10.1002/open.202100289.
Using first-principles calculations, biaxial tensile (ϵ=2 and 4 %) and compressive (ϵ=-2 and -4 %) straining of Na MnSiO lattices resulted into radial distance cut offs of 1.65 and 2 Å, respectively, in the first and second nearest neighbors shell from the center. The Si-O and Mn-O bonds with prominent probability density peaks validated structural stability. Wide-band gap of 2.35 (ϵ=0 %) and 2.54 eV (ϵ=-4 %), and narrow bandgap of 2.24 eV (ϵ=+4 %) estimated with stronger coupling of p-d σ bond than that of the p-d π bond, mainly contributed from the oxygen p-state and manganese d-state. Na -ion diffusivity was found to be enhanced by three orders of magnitude as the applied biaxial strain changed from compressive to tensile. According to the findings, the rational design of biaxial strain would improve the ionic and electronic conductivity of Na MnSiO cathode materials for advanced rechargeable sodium-ion batteries.
通过第一性原理计算，对NaMnSiO晶格施加双轴拉伸（ε = 2%和4%）和压缩（ε = -2%和-4%）应变，导致在距中心的第一和第二近邻壳层中，径向距离截止分别为1.65 Å和2 Å。具有显著概率密度峰的Si-O键和Mn-O键验证了结构稳定性。通过比p-d π键更强的p-d σ键耦合估计，宽带隙为2.35（ε = 0%）和2.54 eV（ε = -4%），窄带隙为2.24 eV（ε = +4%），主要由氧p态和锰d态贡献。随着施加的双轴应变从压缩变为拉伸，发现Na离子扩散率提高了三个数量级。根据这些发现，双轴应变的合理设计将提高用于先进可充电钠离子电池的NaMnSiO正极材料的离子和电子导电性。
