Improvement of electrochemical properties of LiFePO4 fine particles synthesized in ethylene glycol solution resulting from heat treatment

被引：4
作者：
Fujieda, S. [1 ]
Shinoda, K. [1 ]
Suzuki, S. [1 ]
机构：
[1] Tohoku Univ, Inst Multidisciplinary Res Adv Mat, Sendai, Miyagi 980, Japan
来源：
SOLID STATE IONICS | 2014年 / 262卷
关键词：
X-ray absorption spectroscopy; EXAFS; XANES; Polyol; Heat treatment; RAY-ABSORPTION SPECTROSCOPY; IN-SITU; LITHIUM BATTERIES; PHOSPHO-OLIVINES; SOLID-SOLUTION; LIXFEPO4; IRON; NANOPARTICLES; TEMPERATURE; ELECTRODES;
D O I：
10.1016/j.ssi.2013.11.008
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：
Fine crystalline LiFePO4 particles with an average secondary size of about 200 nm were synthesized in ethylene glycol (EG) solution at 393 K. Their molar ratio of Li:Fe:P was about 1.3:1:1, implying the precipitation of an impurity containing extra Li ions. The unit cell volume of crystalline LiFePO4 in heat-treated particles was larger than that in as-synthesized particles. The Fe K absorption edge in the X-ray absorption spectrum was shifted toward a lower energy position by heat treatment. These results suggest that the composition of crystalline LiFePO4 in fine particles is modified by heat treatment because of the reaction with extra Li ions. Additionally, in the radial structural function obtained by Fourier transform of the extended X-ray absorption fine structure oscillation, the Fe-P correlation and Fe-Fe correlation peaks became high due to the heat treatment, implying the rearrangement of FeO6 octahedra and PO4 tetrahedra. In consequence of the above-mentioned structural changes, the electronic capacity of fine particles precipitated in EG solution was enhanced to about 150 mA/h by heat treatment at 673 K. (C) 2013 Elsevier B.V. All rights reserved.
引用
收藏
页码：613 / 616
页数：4
相关论文
共 19 条
[1]   Synthesis and Electrochemical Properties of LiFePO4/Carbon Nanocomposites in Polyol Medium [J].
Choi, E. S. ;
Kim, D. H. ;
Woo, C. H. ;
Choi, C. H. ;
Kim, J. .
JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY, 2010, 10 (05) :3416-3419
[2]   Electronically conductive phospho-olivines as lithium storage electrodes [J].
Chung, SY ;
Bloking, JT ;
Chiang, YM .
NATURE MATERIALS, 2002, 1 (02) :123-128
[3]   Structural investigations of LiFePO4 electrodes and in situ studies by Fe X-ray absorption spectroscopy [J].
Deb, A ;
Bergmann, U ;
Cramer, SP ;
Cairns, EJ .
ELECTROCHIMICA ACTA, 2005, 50 (25-26) :5200-5207
[4]   Size effects on carbon-free LiFePO4 powders [J].
Delacourt, C. ;
Poizot, P. ;
Levasseur, S. ;
Masquelier, C. .
ELECTROCHEMICAL AND SOLID STATE LETTERS, 2006, 9 (07) :A352-A355
[5]   The existence of a temperature-driven solid solution in LixFePO4 for 0 ≤ x ≤ 1 [J].
Delacourt, C ;
Poizot, P ;
Tarascon, JM ;
Masquelier, C .
NATURE MATERIALS, 2005, 4 (03) :254-260
[6]   Synthesis of nanocrystals and morphology control of hydrothermally prepared LiFePO4 [J].
Ellis, B. ;
Kan, Wang Hay ;
Makahnouk, W. R. M. ;
Nazar, L. F. .
JOURNAL OF MATERIALS CHEMISTRY, 2007, 17 (30) :3248-3254
[7]   Surface chemistry of carbon-treated LiFePO4 particles for Li-ion battery cathodes studied by PES [J].
Herstedt, M ;
Stjerndahl, M ;
Nytén, A ;
Gustafsson, T ;
Rensmo, H ;
Siegbahn, H ;
Ravet, N ;
Armand, M ;
Thomas, JO ;
Edström, K .
ELECTROCHEMICAL AND SOLID STATE LETTERS, 2003, 6 (09) :A202-A206
[8]   Electrochemical performance of sol-gel synthesized LiFePO4 in lithium batteries [J].
Hu, YQ ;
Doeff, MM ;
Kostecki, R ;
Fiñones, R .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 2004, 151 (08) :A1279-A1285
[9]   Chemical State of Iron of LiFePO4 during Charge-Discharge Cycles Studied by In-Situ X-ray Absorption Spectroscopy [J].
Inoue, Katsuya ;
Fujieda, Shun ;
Shinoda, Kozo ;
Suzuki, Shigeru ;
Waseda, Yoshio .
MATERIALS TRANSACTIONS, 2010, 51 (12) :2220-2224
[10]   Towards direct synthesis of fct-FePt nanoparticles by chemical route [J].
Jeyadevan, B ;
Hobo, A ;
Urakawa, K ;
Chinnasamy, CN ;
Shinoda, K ;
Tohji, K .
JOURNAL OF APPLIED PHYSICS, 2003, 93 (10) :7574-7576
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