The reaction of charged cathodes with nonaqueous solvents and electrolytes -: I.: Li0.5CoO2

被引:222
作者
MacNeil, DD [1 ]
Dahn, JR
机构
[1] Dalhousie Univ, Dept Chem, Halifax, NS B3H 3J5, Canada
[2] Dalhousie Univ, Dept Phys, Halifax, NS B3H 3J5, Canada
关键词
D O I
10.1149/1.1407245
中图分类号
O646 [电化学、电解、磁化学];
学科分类号
081704 ;
摘要
The thermal decomposition of Li0.5CoO2 was studied by accelerating rate calorimetry and X-ray diffraction. Oxygen loss from the material according to the reaction Li0.5CoO2 --> 0.5 LiCo3O2 + 1/6Co(3)O(4) + O-2 occurs at temperatures above 200 degreesC. By contrast, the reaction of Li0.5CoO2 with ethylene carbonate: diethyl carbonate (EC: DEC) solvent initiates at temperatures as low as 130 degreesC, which is much lower than the decomposition temperature of Li0.5CoO2 itself, and reduction to CoO occurs. We believe that this is caused by the reducing power of the solvent. The heat generated by this reaction is consistent with that expected from the combustion of the solvent by the oxygen liberated during the decomposition of the solid. The reaction of Li0.5CoO2 with xM LiPF6/EC:DEC (0 < x < 1.5) electrolyte was also studied. As the salt concentration is increased, the solvent combustion reaction is suppressed, suggesting that increased LiPF6 concentration can slow the cathode/electrolyte reaction in practical Li-ion cells under conditions of electrical or mechanical abuse. (C) 2001 The Electrochemical Society.
引用
收藏
页码:A1205 / A1210
页数:6
相关论文
共 18 条
[1]   THERMAL-STABILITY OF LIXCOO2, LIXNIO2 AND LAMBDA-MNO2 AND CONSEQUENCES FOR THE SAFETY OF LI-ION CELLS [J].
DAHN, JR ;
FULLER, EW ;
OBROVAC, M ;
VONSACKEN, U .
SOLID STATE IONICS, 1994, 69 (3-4) :265-270
[2]  
de Kolossowsky N, 1933, CR HEBD ACAD SCI, V197, P519
[3]  
Du Pasquier A, 1998, J ELECTROCHEM SOC, V145, P472
[4]  
Hatchard TD, 2000, ELECTROCHEM SOLID ST, V3, P305, DOI 10.1149/1.1391131
[5]   THE PREPARATION, CRYSTALLOGRAPHY, AND MAGNETIC PROPERTIES OF THE LIXCO(1-X)O SYSTEM [J].
JOHNSTON, WD ;
HEIKES, RR ;
SESTRICH, D .
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS, 1958, 7 (01) :1-13
[6]   An autocatalytic mechanism for the reaction of LixCoO2 in electrolyte at elevated temperature [J].
MacNeil, DD ;
Christensen, L ;
Landucci, J ;
Paulsen, JM ;
Dahn, JR .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 2000, 147 (03) :970-979
[7]   Test of reaction kinetics using both differential scanning and accelerating rate calorimetries as applied to the reaction of LixCoO2 in non-aqueous electrolyte [J].
MacNeil, DD ;
Dahn, JR .
JOURNAL OF PHYSICAL CHEMISTRY A, 2001, 105 (18) :4430-4439
[9]  
MATTHEWS J, 2000, ZDNETASIA 1020
[10]   Accelerating rate calorimetry study on the thermal stability of lithium intercalated graphite in electrolyte I. Experimental [J].
Richard, MN ;
Dahn, JR .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 1999, 146 (06) :2068-2077