Details
| Original language | English |
|---|---|
| Article number | 203201 |
| Journal | Journal of Physics Condensed Matter |
| Volume | 24 |
| Issue number | 20 |
| Publication status | Published - 23 May 2012 |
Abstract
We review recent theoretical studies on ion diffusion in (Li 2O) x(B 2O 3) 1x compounds and at the interfaces of Li 2O :B 2O 3 nanocomposite. The investigations were performed theoretically using DFT and HF/DFT hybrid methods with VASP and CRYSTAL codes. For the pure compound B 2O 3, it was theoretically confirmed that the low-pressure phase B 2O 3I has space group P3 121. For the first time, the structure, stability and electronic properties of various low-index surfaces of trigonal B 2O 3I were investigated at the same theoretical level. The (101) surface is the most stable among the considered surfaces. Ionic conductivity was investigated systematically in Li 2O, LiBO 2, and Li 2B 4O 7 solids and in Li 2O:B 2O 3 nanocomposites by calculating the activation energy (E A) for cation diffusion. The Li + ion migrates in an almost straight line in Li 2O bulk whereas it moves in a zig-zag pathway along a direction parallel to the surface plane in Li 2O surfaces. For LiBO 2, the migration along the c direction (E A=0.55eV) is slightly less preferable than that in the xy plane (E A=0.430.54eV). In Li 2B 4O 7, the Li + ion migrates through the large triangular faces of the two nearest oxygen five-vertex polyhedra facing each other where E Ais in the range of 0.270.37eV. A two-dimensional model system of the Li 2O :B 2O 3 interface region was created by the combination of supercells of the Li 2O (111) surface and the B 2O 3 (001) surface. It was found that the interface region of the Li 2O :B 2O 3 nanocomposite is more defective than Li 2O bulk, which facilitates the conductivity in this region. In addition, the activation energy (E A) for local hopping processes is smaller in the Li 2O :B 2O 3 nanocomposite compared to the Li 2O bulk. This confirms that the Li 2O :B 2O 3 nanocomposite shows enhanced conductivity along the phase boundary compared to that in the nanocrystalline Li 2O.
ASJC Scopus subject areas
- Materials Science(all)
- General Materials Science
- Physics and Astronomy(all)
- Condensed Matter Physics
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In: Journal of Physics Condensed Matter, Vol. 24, No. 20, 203201, 23.05.2012.
Research output: Contribution to journal › Review article › Research › peer review
}
TY - JOUR
T1 - The ionic conductivity in lithium-boron oxide materials and its relation to structural, electronic and defect properties
T2 - Insights from theory
AU - Islam, Mazharul M.
AU - Bredow, Thomas
AU - Heitjans, Paul
PY - 2012/5/23
Y1 - 2012/5/23
N2 - We review recent theoretical studies on ion diffusion in (Li 2O) x(B 2O 3) 1x compounds and at the interfaces of Li 2O :B 2O 3 nanocomposite. The investigations were performed theoretically using DFT and HF/DFT hybrid methods with VASP and CRYSTAL codes. For the pure compound B 2O 3, it was theoretically confirmed that the low-pressure phase B 2O 3I has space group P3 121. For the first time, the structure, stability and electronic properties of various low-index surfaces of trigonal B 2O 3I were investigated at the same theoretical level. The (101) surface is the most stable among the considered surfaces. Ionic conductivity was investigated systematically in Li 2O, LiBO 2, and Li 2B 4O 7 solids and in Li 2O:B 2O 3 nanocomposites by calculating the activation energy (E A) for cation diffusion. The Li + ion migrates in an almost straight line in Li 2O bulk whereas it moves in a zig-zag pathway along a direction parallel to the surface plane in Li 2O surfaces. For LiBO 2, the migration along the c direction (E A=0.55eV) is slightly less preferable than that in the xy plane (E A=0.430.54eV). In Li 2B 4O 7, the Li + ion migrates through the large triangular faces of the two nearest oxygen five-vertex polyhedra facing each other where E Ais in the range of 0.270.37eV. A two-dimensional model system of the Li 2O :B 2O 3 interface region was created by the combination of supercells of the Li 2O (111) surface and the B 2O 3 (001) surface. It was found that the interface region of the Li 2O :B 2O 3 nanocomposite is more defective than Li 2O bulk, which facilitates the conductivity in this region. In addition, the activation energy (E A) for local hopping processes is smaller in the Li 2O :B 2O 3 nanocomposite compared to the Li 2O bulk. This confirms that the Li 2O :B 2O 3 nanocomposite shows enhanced conductivity along the phase boundary compared to that in the nanocrystalline Li 2O.
AB - We review recent theoretical studies on ion diffusion in (Li 2O) x(B 2O 3) 1x compounds and at the interfaces of Li 2O :B 2O 3 nanocomposite. The investigations were performed theoretically using DFT and HF/DFT hybrid methods with VASP and CRYSTAL codes. For the pure compound B 2O 3, it was theoretically confirmed that the low-pressure phase B 2O 3I has space group P3 121. For the first time, the structure, stability and electronic properties of various low-index surfaces of trigonal B 2O 3I were investigated at the same theoretical level. The (101) surface is the most stable among the considered surfaces. Ionic conductivity was investigated systematically in Li 2O, LiBO 2, and Li 2B 4O 7 solids and in Li 2O:B 2O 3 nanocomposites by calculating the activation energy (E A) for cation diffusion. The Li + ion migrates in an almost straight line in Li 2O bulk whereas it moves in a zig-zag pathway along a direction parallel to the surface plane in Li 2O surfaces. For LiBO 2, the migration along the c direction (E A=0.55eV) is slightly less preferable than that in the xy plane (E A=0.430.54eV). In Li 2B 4O 7, the Li + ion migrates through the large triangular faces of the two nearest oxygen five-vertex polyhedra facing each other where E Ais in the range of 0.270.37eV. A two-dimensional model system of the Li 2O :B 2O 3 interface region was created by the combination of supercells of the Li 2O (111) surface and the B 2O 3 (001) surface. It was found that the interface region of the Li 2O :B 2O 3 nanocomposite is more defective than Li 2O bulk, which facilitates the conductivity in this region. In addition, the activation energy (E A) for local hopping processes is smaller in the Li 2O :B 2O 3 nanocomposite compared to the Li 2O bulk. This confirms that the Li 2O :B 2O 3 nanocomposite shows enhanced conductivity along the phase boundary compared to that in the nanocrystalline Li 2O.
UR - http://www.scopus.com/inward/record.url?scp=84860321273&partnerID=8YFLogxK
U2 - 10.1088/0953-8984/24/20/203201
DO - 10.1088/0953-8984/24/20/203201
M3 - Review article
AN - SCOPUS:84860321273
VL - 24
JO - Journal of Physics Condensed Matter
JF - Journal of Physics Condensed Matter
SN - 0953-8984
IS - 20
M1 - 203201
ER -