Synthesis conditions and oxygen stoichiometry effects on Li insertion into the spinel LiMn[sub 2]O[sub 4]
Synthesis conditions and oxygen stoichiometry effects on Li insertion into the spinel LiMn[sub 2]O[sub 4]
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DOI：
10.1149/1.2054941
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发表时间：
1994-06
影响因子：
3.9
通讯作者：
J. Tarascon;W. Mckinnon;F. Coowar;T. Bowmer;G. Amatucci;D. Guyomard
中科院分区：
文献类型：
--
作者：
J. Tarascon;W. Mckinnon;F. Coowar;T. Bowmer;G. Amatucci;D. Guyomard
使用一种新的电解质组合物，这是稳定的抗氧化高达5 V，从尖晶石LiMn[sub 2]O[sub 4]的锂的完全电化学脱嵌，进行了研究。在4.5和4.9 V附近的两个新的可逆氧化还原峰的起源进行了检查。与这些峰相关的容量取决于Li[sub x]Mn[sub 2]O[sub 4]中的标称组成x和合成条件（退火温度和冷却速率），因此可以用作电化学优化的LiMn[sub 2]O[sub 4]粉末的指标。作者提出的证据表明，这些峰值与局部结构缺陷。对Li[sub x]Mn[sub 2]O[sub 4]粉末的热重测量（TGA）显示在1，000 C下氧的可逆损失可达到5%。作者发现，这种重量损失的一部分与立方LiMn[sub 2]O[sub 4]转化为新的四方尖晶石相，然后该相分解为正交LiMnO[sub 2]相和其他产物有关。本文报道了这种新型四元LiMn[sub 2]O[sub 4]尖晶石的单相制备及其电化学性能。
Using a new electrolyte composition which is stable against oxidation up to 5 V, the full electrochemical deintercalation of lithium from the spinel LiMn[sub 2]O[sub 4], is studied. The origin of two new reversible oxidation-reduction peaks near 4.5 and 4.9 V are examined. The capacity associated with these peaks depends on both the nominal composition x in Li[sub x]Mn[sub 2]O[sub 4] and the synthesis conditions (annealing temperatures and cooling rates), and thereby can be used as an indicator for electrochemically optimized LiMn[sub 2]O[sub 4] powders. The authors present evidence that these peaks are related to local structural defects. Thermogravimetric measurements (TGA) on Li[sub x]Mn[sub 2]O[sub 4] powders show a reversible loss of oxygen that can reach 5% at 1,000 C. The authors find that some of this weight loss is associated with the conversion of cubic LiMn[sub 2]O[sub 4] to a new tetragonal spinel phase and then to the decomposition of this phase into the orthorhombic LiMnO[sub 2] phase plus other products. This new tetragonal LiMn[sub 2]O[sub 4] spinel is prepared as a single phase, and its electrochemical properties are reported.