Optimized Synthetic Conditions of LiNi0.5Co0.2Mn0.3O2 Cathode Materials for High Rate Lithium Batteries via Co-Precipitation Method
Optimized Synthetic Conditions of LiNi0.5Co0.2Mn0.3O2 Cathode Materials for High Rate Lithium Batteries via Co-Precipitation Method
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DOI：
10.1149/2.004302jes
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发表时间：
2013-01-01
影响因子：
3.9
通讯作者：
Cho, Jaephil
中科院分区：
文献类型：
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作者：
Noh, Mijung;Cho, Jaephil
采用共沉淀法制备了Ni0.5Co0.2Mn0.3(OH)(2)前驱体，优化了LiNi0.5Co0.2Mn0.3O2正极材料的合成条件，以提高其倍率性能和60℃高温性能。在pH=11，NH3/MSO4=0.8，搅拌速度为1000rpm的条件下，制得了球状Ni0.5Co0.2Mn0.3(OH)(2)前驱体，振实密度为2.2GCM(-3)，粒度为7微米。利用这些优化的前驱体制备了平均粒径为7微米、振实密度为2.6GCM(-3)的LiNi0.5Co0.2Mn0.3O2材料(记为LU3)，并对其在23℃和60℃下的电化学性能进行了表征。优化后的样品在3~4.5V的锂半电池中，0.1C倍率下的首次放电容量为204mAhg，库仑效率为92%。此外，在7C倍率下，它保持了50%的容量保持率(电极密度为2.9GCC(-1))，而商业样品在相同的倍率下仅保持了37%(电极密度为2.6GCC(-1))。换句话说，LU3阴极在290W/kg的比功率下提供了380 Wh/kg的比能量，而CS阴极在220W/kg的功率下只提供了206 Wh/kg的比能量。在60℃时，LU3样品的容量保留率高于商用样品。循环后样品的XPS和TEM结果表明，Ni原子在表面的分布对维持循环过程中的结构稳定性起着关键作用。(C)2012年电化学会。[DOI：10.1149/2.004302jes]版权所有。
A synthetic condition for LiNi0.5Co0.2Mn0.3O2 cathode materials to improve their rate capability and elevated temperature performance at 60 degrees C was optimized with Ni0.5Co0.2Mn0.3(OH)(2) precursors prepared using a co-precipitation method. Under conditions of pH = 11, NH3/MSO4 = 0.8, and stirring speed = 1000 rpm, spherical Ni0.5Co0.2Mn0.3(OH)(2) precursors with a tap density of 2.2 gcm(-3) and particle size of 7 mu m were successfully obtained. Using these optimized precursors, LiNi0.5Co0.2Mn0.3O2 material (denoted as LU3) with an average particle size and tap density of 7 mu m and 2.6 gcm(-3), respectively, was prepared and electrochemical performances at 23 degrees C and 60 degrees C were characterized. The first discharge capacity of the optimized sample was 204 mAh/g with a coulombic efficiency of 92% at 0.1C rate in a lithium half-cell between 3 and 4.5V. Further, it maintained 50% capacity retention (electrode density of 2.9 gcc(-1)) at a 7C rate, while a commercial sample showed only 37% (electrode density of 2.6 gcc(-1)) at the same rate under electrode. In other words, the LU3 cathode delivered specific energy of 380 Wh/kg under specific power of 290W/kg, while a CS cathode delivers only specific energy of 206 Wh/kg under power of 220W/kg. At 60 degrees C, the LU3 sample had higher capacity retention than the commercial one. XPS and TEM results of the samples after cycling showed that distribution of Ni atoms on the surface played a key role in sustaining the structural stability during the cycling. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.004302jes] All rights reserved.