Stabilities and electronic properties of lithium titanium oxide anode material for lithium ion battery

Autor: Hong-Bin Qiao, Shu Jie, Ying Xie, An-Na Zhou, Yan-Rong Zhu, Ting-Feng Yi
Rok vydání: 2012
Předmět:
Zdroj: Journal of Power Sources. 198:318-321
ISSN: 0378-7753
DOI: 10.1016/j.jpowsour.2011.10.014
Popis: A theoretical study of the structural, elastic and electronic properties of spinel LiTi 2 O 4 anode has been performed by density functional theory (DFT) plane-wave pseudopotential method. The independent elastic constants, shear modulus ( G ), bulk modulus ( B ), and Young's modulus ( E ) are evaluated, respectively. The results suggest that cubic LiTi 2 O 4 is mechanically stable. The G / B ratio of 0.584 indicates the ductility of LiTi 2 O 4 is good. The electron density difference of LiTi 2 O 4 shows that the O 2p orbits overlap effectively with Ti 3d ones, confirming the formations of strong covalent bonds between them, while Li is fully ionized in the lattice. The formation enthalpy for LiTi 2 O 4 is calculated to be −2070.723 ± 1.6 kJ mol −1 . The strong covalent bonds between O and Ti atoms are not only responsible for the excellent mechanical stabilities but also very crucial for the thermodynamic stability of LiTi 2 O 4 compound. Furthermore, in Li 2 Ti 2 O 4 compound, the full occupation of 16(c) sites by Li + not only leads to a smaller C 12 value but also leads to a much larger C 44 one. Therefore, the plasticity and ductility of the Li 2 Ti 2 O 4 become poor in comparison to LiTi 2 O 4 , while the thermodynamic stability of Li 2 Ti 2 O 4 can be further improved after the Li + intercalation of LiTi 2 O 4 .
Databáze: OpenAIRE
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