Effects of Ag coating on the structural and electrochemical properties of LiNi0.8Co0.1Mn0.1O2 as cathode material for lithium ion batteries
Effects of Ag coating on the structural and electrochemical properties of LiNi0.8Co0.1Mn0.1O2 as cathode material for lithium ion batteries
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DOI：
10.1016/j.electacta.2019.135054
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发表时间：
2019-12
影响因子：
6.6
通讯作者：
Hui-lan Sun;Yafei Zhang;Wen Li;Di Zhang;Wang Qiujun-;Bo Wang
中科院分区：
文献类型：
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作者：
Hui-lan Sun;Yafei Zhang;Wen Li;Di Zhang;Wang Qiujun-;Bo Wang
以共沉淀法制备的Ni0.8Co0.1Mn0.1（OH）2为前驱体，首次在其表面包覆金属Ag，合成了富Ni层状氧化物LiNi0.8Co0.1Mn0.1O2（NCM 811）正极材料。X射线衍射结果表明，Ag+离子很难掺杂到NCM 811颗粒中，Li+/Ni 2+的离子混合程度降低。用扫描电镜和透射电镜证实了在NCM 811材料表面形成了非晶态的银镀层。X射线光电子能谱表明，与纯NCM 811相比，银涂层NCM 811材料表面有更多的Ni 3+离子。恒流充放电测试表明，在2.8 ~ 4.3 V电压范围内，1wt% Ag包覆的NCM 811的首次放电容量为209.1 mAh·g− 1，90次循环后的容量保持率为90.5%（上级），与纯NCM 811（87.9%）相比，其循环稳定性有了很大提高。电化学阻抗谱表明，Ag包覆后的电极极化降低，电子电导率提高，Li+扩散系数增大。这些结果清楚地表明，Ag涂层可以提高NCM 811材料的结构和电化学性能。
Ni-rich layered oxide LiNi0.8Co0.1Mn0.1O2(NCM811) cathode materials are synthesized using Ni0.8Co0.1Mn0.1(OH)2precursors obtained from a co-precipitation reaction and then coated with of metal Ag for the first time. X-ray diffraction results verify that Ag+ions can hardly dope into the bulk NCM811 particles and the ion mixing degree of Li+/Ni2+has been reduced. Amorphous Ag coating layers formed on the surface of Ag coated NCM811 materials are proved by scanning electron microscope and transmission electron microscope. X-ray photoelectron spectroscopy demonstrates that more Ni3+ions on the surface of Ag coated NCM811 materials than that of pure NCM811. Galvanostatic charge-discharge tests indicate that 1wt% Ag coated NCM811 exhibits initial discharge capacity of 209.1 mAh·g−1and superior capacity retention of 90.5% after 90 cycles between 2.8 and 4.3 V, which shows greatly improved cycling stability compared with the pure NCM811 (87.9%). After Ag coating, reduced electrode polarization is certified by cyclic voltammetry, and better electron conductivity and higher Li+diffusion coefficient are testified by electrochemical impedance spectroscopy. These results clearly indicate Ag coating can enhance the structural and electrochemical properties of NCM811 materials.