Effects of Equimolar Co3+ and Ni2+ Co-Doping on the Electrochemical Properties of Spinel LiMn2-2xNixCoxO4 Prepared by Solid-State Reaction Method
Effects of Equimolar Co3+ and Ni2+ Co-Doping on the Electrochemical Properties of Spinel LiMn2-2xNixCoxO4 Prepared by Solid-State Reaction Method
复制标题
等摩尔Co3和Ni2共掺杂对固相反应法制备尖晶石LiMn2-2xNixCoxO4电化学性能的影响
DOI：
10.1166/nnl.2017.2372
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发表时间：
2017
影响因子：
--
通讯作者：
Li Ding
中科院分区：
文献类型：
--
作者：
Jiang Jianbing;Gong Guo;Li Changyun;Li Ding
以Li2CO3、球形Mn3O4、球形Ni(OH)2和球形Co3O4为原料，采用固相反应法制备了尖晶石LiMn2 -2x Ni x Co x O4 （x = 0、0.01、0.03和0.05）正极材料。用x射线和扫描电镜对LiMn2 -2x Ni x Co x O4的晶体结构和形貌进行了表征。所得样品结晶度良好，均为LiMn2O4的立方尖晶石结构，无杂质峰。等摩尔Co3+和Ni2+离子分别取代Mn3+和Mn4+离子完全占据八面体（16d）位置。采用恒流充放电试验、循环伏安法（CV）和电化学阻抗谱（EIS）研究了等摩尔Co3+和Ni2+离子共掺杂对LiMn2 -2x Ni x Co x O4电化学性能的影响。结果表明，等摩尔Co3+和Ni2+离子共掺杂LiMn2O4具有更好的循环保留性能和速率性能。最佳limn1.94 ni0.03 co0.030 o4的初始放电容量为116 mAh/g，在3.0-4.3 V电压范围内，1C下循环300次后放电容量为109.2 mAh/g。其容量保持率可达94.1%，远高于未掺杂的LiMn2O4。
Spinel LiMn2 –2x Ni x Co x O4 (x = 0, 0.01, 0.03, and 0.05) cathode materials were successfully synthesized by solid-state reaction method with Li2CO3, spherical Mn3O4, spherical Ni(OH)2 and spherical Co3O4 as raw materials. The crystal structures and morphologies for LiMn2 –2x Ni x Co x O4 were characterized by X-ray and scanning electron microscopy (SEM), respectively. All the obtained samples with good crystallinity were identified as cubic spinel structure of LiMn2O4 and no impurity peaks were observed. Equimolar Co3+ and Ni2+ ions completely occupied the octahedral (16d) site to substitute Mn3+ and Mn4+ ions, respectively. The effects of equimolar Co3+ and Ni2+ ions co-doping on the electrochemical properties of LiMn2 –2x Ni x Co x O4 were investigated by galvanostatic charge–discharge test, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). Results showed that the equimolar Co3+ and Ni2+ ions co-doping LiMn2O4 presented better cycling retention and rate performance. The initial discharge capacity was 116 mAh/g for the optimal LiMn1.94Ni0.03Co0.03O4, and 109.2 mAh/g remained after 300 cycles at 1C in the voltage range 3.0–4.3 V. The capacity retention could reach 94.1%, which was far higher than that for the undoped LiMn2O4.