Phase diagram and electrochemical properties of mixed olivines from first-principles calculations

被引:77
作者
Malik, Rahul [1 ]
Zhou, Fei [2 ]
Ceder, Gerbrand [1 ]
机构
[1] MIT, Dept Mat Sci & Engn, Cambridge, MA 02139 USA
[2] Univ Calif Los Angeles, Dept Mat Sci & Engn, Los Angeles, CA 90095 USA
来源
PHYSICAL REVIEW B | 2009年 / 79卷 / 21期
基金
美国国家科学基金会;
关键词
density functional theory; electrochemical electrodes; electrochemistry; iron compounds; lithium compounds; manganese compounds; Monte Carlo methods; oxidation; phase diagrams; reduction (chemical); solid solubility; solid solutions; LITHIUM BATTERIES; HYDROTHERMAL SYNTHESIS; QUENCHED DISORDER; CATHODE MATERIALS; SOLID-SOLUTION; LIXMPO4; M; SYSTEMS; LI-X(MNYFE1-Y)PO4; MECHANISM; LIXFEPO4;
D O I
10.1103/PhysRevB.79.214201
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Using first-principles calculations, we study the effect of cation substitution on the transition-metal sublattice in phospho-olivines, with special attention given to the Li(x)(Fe(1-y)Mn(y))PO(4) system. We use a cluster expansion model derived from first-principles with Monte Carlo simulations to calculate finite-T phase diagrams, voltage curves, and solubility limits of the system. The phase diagram of Li(x)(Fe(1-y)Mn(y))PO(4) shows two low-temperature miscibility gaps separated by a solid solution phase centered at Li composition x approximate to y, which corresponds to a state where most Fe ions are oxidized and most Mn are not. This intermediate low-T solid solution is stabilized by the dilution of phase-separating interactions caused by the disorder of redox potentials on the transition-metal sites. The calculated voltage curves show two plateaus at similar to 4-4.2 V and similar to 3.5-3.7 V, corresponding to the Mn(3+)/Mn(2+) and Fe(3+)/Fe(2+) redox couples, respectively, with an extended sloping region in between corresponding to the low-T solid solution phase. In agreement with experiment, we find that the Mn(3+)/Mn(2+) (Fe(3+)/Fe(2+)) voltage is decreased (increased) by Fe (Mn) substitution. We explain this by considering the energy of the solid solution which is the discharged (charged) state for these redox couples and argue that such changes are generic to all mixed olivine systems. We also find reduced phase transformation polarization on both plateaus which we attribute to the decreased composition difference between the oxidized and reduced state for each redox couple.
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页数:7
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共 35 条
  • [1] ROUNDING OF 1ST-ORDER PHASE-TRANSITIONS IN SYSTEMS WITH QUENCHED DISORDER
    AIZENMAN, M
    WEHR, J
    [J]. PHYSICAL REVIEW LETTERS, 1989, 62 (21) : 2503 - 2506
  • [2] ABSENCE OF TEMPERATURE-DRIVEN 1ST-ORDER PHASE-TRANSITIONS IN SYSTEMS WITH RANDOM BONDS
    BERKER, AN
    [J]. JOURNAL OF APPLIED PHYSICS, 1991, 70 (10) : 5941 - 5945
  • [3] BERKER AN, 1993, PHYSICA A, V194, P72, DOI 10.1016/0378-4371(93)90341-Z
  • [4] Local structure in the Li-ion battery cathode material Lix(MnyFe1-y)PO4 for 0 < x ≤ 1 and y=0.0, 0.5 and 1.0
    Burba, Christopher A.
    Frech, Roger
    [J]. JOURNAL OF POWER SOURCES, 2007, 172 (02) : 870 - 876
  • [5] Application of first-principles calculations to the design of rechargeable Li-batteries
    Ceder, G
    Aydinol, MK
    Kohan, AF
    [J]. COMPUTATIONAL MATERIALS SCIENCE, 1997, 8 (1-2) : 161 - 169
  • [6] The hydrothermal synthesis and characterization of olivines and related compounds for electrochemical applications
    Chen, Jiajun
    Vacchio, Michael J.
    Wang, Shijun
    Chernova, Natalya
    Zavalij, Peter Y.
    Whittingham, M. Stanley
    [J]. SOLID STATE IONICS, 2008, 178 (31-32) : 1676 - 1693
  • [7] Hydrothermal synthesis of cathode materials
    Chen, Jiajun
    Wang, Shijun
    Whittingham, M. Stanley
    [J]. JOURNAL OF POWER SOURCES, 2007, 174 (02) : 442 - 448
  • [8] The existence of a temperature-driven solid solution in LixFePO4 for 0 ≤ x ≤ 1
    Delacourt, C
    Poizot, P
    Tarascon, JM
    Masquelier, C
    [J]. NATURE MATERIALS, 2005, 4 (03) : 254 - 260
  • [9] Lithium deintercalation in LiFePO4 nanoparticles via a domino-cascade model
    Delmas, C.
    Maccario, M.
    Croguennec, L.
    Le Cras, F.
    Weill, F.
    [J]. NATURE MATERIALS, 2008, 7 (08) : 665 - 671
  • [10] Phase diagram of LixFePO4
    Dodd, JL
    Yazami, R
    Fultz, B
    [J]. ELECTROCHEMICAL AND SOLID STATE LETTERS, 2006, 9 (03) : A151 - A155