Co-precipitation synthesis of Ni_0.6Co_0.2Mn_0.2(OH)₂ precursor and characterization of LiNi_0.6Co_0.2Mn_0.2O₂ cathode material for secondary lithium batteries

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• 作者：Longwei Liang ; Ke Du ; ^{dukeben76@yahoo.com.cn" class="auth_mail} ; ^{csulllw198611@163.com" class="auth_mail} ; Zhongdong Peng ; Yanbing Cao ; Jianguo Duan ; Jianbing Jiang ; Guorong Hu
• 关键词：Lithium secondary batteries ; LiNi0.6Co0.2Mn0.2O2 ; Co-precipitation ; Electrochemical properties
• 刊名：Electrochimica Acta
• 出版年：1 June 2014
• 年：2014
• 卷：130
• 期：Complete
• 页码：82-89
• 全文大小：3657 K

文摘

LiNi_0.6Co_0.2Mn_0.2O₂ cathode materials were synthesized from spherical and homogeneous mixed metal hydroxide Ni_0.6Co_0.2Mn_0.2(OH)₂ which was prepared by co–precipitation method. The synthetic conditions of the metal hydroxide, such as pH, amount of chelating, stirring speed, temperature, etc. were studied in detail. The homogeneous and spherical Ni_0.6Co_0.2Mn_0.2(OH)₂ precursor obtained in the optimized synthetic conditions had a high tap–density of 1.94 g cm⁻³. A well–ordered layer–structured and spherical LiNi_0.6Co_0.2Mn_0.2O₂ cathode material, with the tap–density of 2.59 g cm⁻³, was fabricated by calcinating the as-prepared Ni_0.6Co_0.2Mn_0.2(OH)₂ precursor and 5% excess LiOH·H₂O at 820 °C in the flowing oxygen. The crystal structure, morphology and electrochemical properties of the precursors and final products were investigated by using X–ray diffractometry, scanning electron microscopy, charge–discharge test and C–V method. In the voltage ranges of 2.8–4.3, 4.4 and 4.5 V, the initial discharge capacities of LiNi_0.6Co_0.2Mn_0.2O₂ at 1 C rate were 172.1, 177.9 and 182.5 mAh g⁻¹, respectively, while the corresponding discharge capacity retention ratios after 100 cycles were 94.3%, 90.7% and 85.4%. For elevated temperature operation (60 °C), the resulted capacity was as high as 196.9mAh g⁻¹ in the voltage range of 2.8–4.3 V and retained 89.7% after 100 cycles.