Formation and diffusion of vacancy-polaron complex in olivine-type LiMnPO4 and LiFePO4

被引:43
作者
Asari, Yusuke [1 ]
Suwa, Yuji [1 ]
Hamada, Tomoyuki [1 ]
机构
[1] Hitachi Ltd, Adv Res Lab, Saitama 3500395, Japan
来源
PHYSICAL REVIEW B | 2011年 / 84卷 / 13期
关键词
AUGMENTED-WAVE METHOD; LITHIUM BATTERIES; CATHODE MATERIALS; ELECTRODE MATERIALS; MAGNETIC-PROPERTIES; LIXMPO4; M; LIXFEPO4; TRANSPORT; MODEL; ION;
D O I
10.1103/PhysRevB.84.134113
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Formation and diffusion of a vacancy-polaron complex in olivine-type cathode-active materials, namely, LiMPO4 (M = Fe, Mn), were theoretically investigated by using the first-principles density functional theory within a framework of GGA + U method. It is shown that a lithium vacancy and a corresponding hole-polaron form the complex at the fully lithiated limit owing to lattice distortion and Coulomb interaction between them. It is also shown that the formation energy of the complex in LiMnPO4 is 0.19 eV higher than that in LiFePO4, since a hole polaron in LiMnPO4 is not sufficiently relaxed. As a result, the nucleation rate of MnPO4 phase in LiMnPO4 is 10(-3) times slower than that in LiFePO4 and represents the main difference between the kinetics in the initial stage of charging of the two olivine materials. It was also found that the activation energy of the complex diffusion is limited by vacancy hopping in LiMnPO4, while it is determined by both vacancy hopping and polaron hopping in LiFePO4. The activation energy in LiMnPO4, 0.38 eV, is comparable with that in LiFePO4, 0.42 eV. The calculated potential energy profile, showed that the minimum energy path of the diffusing lithium in LiMnPO4 has the same winding shape as that in LiFePO4.
引用
收藏
页数:7
相关论文
共 46 条
[1]   Structural and magnetic properties of LiFePO4 and lithium extraction effects [J].
Ait-Salah, A. ;
Dodd, J. ;
Mauger, A. ;
Yazami, R. ;
Gendron, F. ;
Julien, C. M. .
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE, 2006, 632 (8-9) :1598-1605
[2]   Ionic and electronic transport in single crystalline LiFePO4 grown by optical floating zone technique [J].
Amin, R. ;
Maier, J. ;
Balaya, P. ;
Chen, D. P. ;
Lin, C. T. .
SOLID STATE IONICS, 2008, 179 (27-32) :1683-1687
[3]   Effect of annealing on transport properties of LiFePO4:: Towards a defect chemical model [J].
Amin, R. ;
Maier, J. .
SOLID STATE IONICS, 2008, 178 (35-36) :1831-1836
[4]   BAND THEORY AND MOTT INSULATORS - HUBBARD-U INSTEAD OF STONER-I [J].
ANISIMOV, VI ;
ZAANEN, J ;
ANDERSEN, OK .
PHYSICAL REVIEW B, 1991, 44 (03) :943-954
[5]   PROJECTOR AUGMENTED-WAVE METHOD [J].
BLOCHL, PE .
PHYSICAL REVIEW B, 1994, 50 (24) :17953-17979
[6]   Solid Solution Phases in the Olivine-Type LiMnPO4/MnPO4 System [J].
Chen, Guoying ;
Richardson, Thomas J. .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 2009, 156 (09) :A756-A762
[7]   Toward understanding of electrical limitations (electronic, ionic) in LiMPO4 (M = Fe, Mn) electrode materials [J].
Delacourt, C ;
Laffont, L ;
Bouchet, R ;
Wurm, C ;
Leriche, JB ;
Morcrette, M ;
Tarascon, JM ;
Masquelier, C .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 2005, 152 (05) :A913-A921
[8]   Lithium deintercalation in LiFePO4 nanoparticles via a domino-cascade model [J].
Delmas, C. ;
Maccario, M. ;
Croguennec, L. ;
Le Cras, F. ;
Weill, F. .
NATURE MATERIALS, 2008, 7 (08) :665-671
[9]   Electron-energy-loss spectra and the structural stability of nickel oxide: An LSDA+U study [J].
Dudarev, SL ;
Botton, GA ;
Savrasov, SY ;
Humphreys, CJ ;
Sutton, AP .
PHYSICAL REVIEW B, 1998, 57 (03) :1505-1509
[10]   Small polaron hopping in LixFePO4 solid solutions:: Coupled lithium-ion and electron mobility [J].
Ellis, Brian ;
Perry, Laura K. ;
Ryan, Dominic H. ;
Nazar, L. F. .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 2006, 128 (35) :11416-11422