Room-temperature miscibility gap in LixFePO4

被引:489
作者
Yamada, A
Koizumi, H
Nishimura, SI
Sonoyama, N
Kanno, R
Yonemura, M
Nakamura, T
Kobayashi, Y
机构
[1] Tokyo Inst Technol, Grad Sch Sci & engn, Dept Elect Chem, Interdisciplinary Grad Sch Sci & Engn, Yokohama, Kanagawa 2268502, Japan
[2] Univ Hyogo, Grad Sch Engn, Dept Elect Engn & Comp Sci, Himeji, Hyogo 6712201, Japan
[3] Ibaraki Univ, Grad Sch Sci & Engn, Inst Appl Beam Sci, Hitachi, Ibaraki 3168511, Japan
[4] Cent Res Inst Elect Power Ind, Komae, Tokyo 2018511, Japan
关键词
D O I
10.1038/nmat1634
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The rechargeable lithium-ion cell is an advanced energy-storage system. However, high cost, safety hazards, and chemical instability prohibit its use in large-scale applications. An alternative cathode material, LiFePO(4), solves these problems, but has a kinetic problem involving strong electron/hole localization(1). One reason for this is believed to be the limited carrier density in the fixed monovalent Fe(3+)PO(4)/LiFe(2+)PO(4) two-phase electrode reaction in Li(x)FePO(4). Here, we provide experimental evidence that LixFePO4, at room temperature, can be described as a mixture of the Fe(3+)/Fe(2+) mixed-valent intermediate Li(alpha)FePO(4) and Li(1-beta)FePO(4) phases. Using powder neutron diffraction, the site occupancy numbers for lithium in each phase were refined to be alpha = 0.05 and 1-beta = 0.89. The corresponding solid solution ranges outside themiscibility gap (0 < x < alpha, 1-beta < x < 1) were detected by the anomaly in the configurational entropy, and also by the deviation of the open-circuit voltage from the constant equilibrium potential. These findings encourage further improvement of this important class of compounds at ambient temperatures.
引用
收藏
页码:357 / 360
页数:4
相关论文
共 21 条
  • [1] Lithium extraction/insertion in LiFePO4:: an X-ray diffraction and Mossbauer spectroscopy study
    Andersson, AS
    Kalska, B
    Häggström, L
    Thomas, JO
    [J]. SOLID STATE IONICS, 2000, 130 (1-2) : 41 - 52
  • [2] Electronically conductive phospho-olivines as lithium storage electrodes
    Chung, SY
    Bloking, JT
    Chiang, YM
    [J]. NATURE MATERIALS, 2002, 1 (02) : 123 - 128
  • [3] ENTROPY OF THE INTERCALATION COMPOUND LIXMO6SE8 FROM CALORIMETRY OF ELECTROCHEMICAL-CELLS
    DAHN, JR
    MCKINNON, WR
    MURRAY, JJ
    HAERING, RR
    MCMILLAN, RS
    RIVERSBOWERMAN, AH
    [J]. PHYSICAL REVIEW B, 1985, 32 (05): : 3316 - 3318
  • [4] PHASE-DIAGRAM OF LIXMO6SE8 FOR 0 LESS-THAN X LESS-THAN 1 FROM INSITU X-RAY STUDIES
    DAHN, JR
    MCKINNON, WR
    [J]. PHYSICAL REVIEW B, 1985, 32 (05): : 3003 - 3005
  • [5] 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
  • [6] THE NASICON-TYPE TITANIUM PHOSPHATES LITI2(PO4)3, NATI2(PO4)3 AS ELECTRODE MATERIALS
    DELMAS, C
    NADIRI, A
    SOUBEYROUX, JL
    [J]. SOLID STATE IONICS, 1988, 28 : 419 - 423
  • [7] Nano-network electronic conduction in iron and nickel olivine phosphates
    Herle, PS
    Ellis, B
    Coombs, N
    Nazar, LF
    [J]. NATURE MATERIALS, 2004, 3 (03) : 147 - 152
  • [8] Electrochemical and calorimetric approach to spinel lithium manganese oxide
    Kobayashi, Y
    Kihira, N
    Takei, K
    Miyashiro, H
    Kumai, K
    Terada, N
    Ishikawa, R
    [J]. JOURNAL OF POWER SOURCES, 1999, 81 : 463 - 466
  • [9] Precise electrochemical calorimetry of LiCoO2/graphite lithium-ion cell -: Understanding thermal behavior and estimation of degradation mechanism
    Kobayashi, Y
    Miyashiro, H
    Kumai, K
    Takei, K
    Iwahori, T
    Uchida, I
    [J]. JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 2002, 149 (08) : A978 - A982
  • [10] Li conductivity in LixMPO4 (M = Mn, Fe, Co, Ni) olivine materials
    Morgan, D
    Van der Ven, A
    Ceder, G
    [J]. ELECTROCHEMICAL AND SOLID STATE LETTERS, 2004, 7 (02) : A30 - A32