Defect formation energy and magnetic structure of shape memory alloys Ni–X–Ga (X=Mn, Fe, Co) by first principle calculation

2010 ◽  
Vol 108 (6) ◽  
pp. 064904 ◽  
Author(s):  
J. Bai ◽  
J. M. Raulot ◽  
Y. D. Zhang ◽  
C. Esling ◽  
X. Zhao ◽  
...  

The defect graphite will change the electrochemical properties of the aluminium-ion batteries. However, the theoretical research on the defect-free graphite as cathode material for aluminium-ion batteries remain uncertain. Therefore, the objective of this paper is to develop the theoretical prediction of defect graphite to be used in the aluminium-ion batteries analysis. The structural properties of graphite and vacancy point defect of graphite were calculated using the first principle calculation. The generalized gradient approximation and van der Waals correction (vdW-D3) implemented to the calculation. The validation of the methodology on the defect-free graphite is evaluated with the experiment and other theoretical prediction. After that, the lattice constants of the defect graphite were evaluated and calculate the formation energy. The results show that the lattice constant of defect-free graphite was closer to the experimental values compared to other theoretical prediction. However, the atomic distances near to the vacancy point observed slightly lower than other theoretical prediction using different exchange correlation approximation. The formation energy calculated for monovacancy and divacancy was 7. 92 eV and 7.34 eV, respectively. As a conclusion, the structural properties obtained in this calculation could be references in the development of the defect cathode analysis in the aluminium ion batteries.


2019 ◽  
Vol 125 (9) ◽  
pp. 094302
Author(s):  
H. Li ◽  
H. N. Du ◽  
X. W. He ◽  
Y. Y. Shen ◽  
H. X. Zhang ◽  
...  

2013 ◽  
Vol 652-654 ◽  
pp. 554-558
Author(s):  
Xin Min Min ◽  
Xuchao Wang

The relations between electronic structure and thermoelectric property of misfit layered cobaltite of Ca3Co4O9 and La-doped series are studied from the calculation by density function and discrete variation method (DFT-DVM). The highest valence band (HVB) and the lowest conduction band (LCB) near Fermi level are only mainly from O 2p and Co 3d in Ca2CoO3 layer. Therefore, the semiconductor, or thermoelectric property of Ca3Co4O9 should be mainly from Ca2CoO3 layer, but have no direct relation to the CoO2 layer, which is consistent with that binary oxides hardly have thermoelectric property, but trinary oxide compounds have quite good thermoelectric property. With the amount of La-doped increase, the gap between HVB and LCB firstly decrease, then reaches the minimum, finally increase. The gap affects the thermoelectric property. Therefore, there is a best amount of Na-doped to improve thermoelectric property, which is consistent with the experiment.


2017 ◽  
Vol 896 ◽  
pp. 120-127 ◽  
Author(s):  
Ting Ting Zhou ◽  
Chuan Zhen Huang ◽  
Ming Dong Yi

First-principle calculation is carried out on Al2O3(012)/SiC(310) interface model. It can be concluded from the electronic density and population analysis that Al-C and O-Si located at grain boundary primarily contribute to the interface bonding strength and creep resistance property. The electronic charges in grain boundaries and grains are compared with each other. And the valence electrons are found to be redistributed. The relationship of all kinds of chemical bonds in grains and grain boundary of the interface model is analyzed. Also the toughening mechanism of Al2O3/SiC multi-phase ceramic tool materials is explained in nano-scale.


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