Improved electrochemical properties of BiF3/C cathode via adding amorphous AlPO4 for lithium-ion batteries
Improved electrochemical properties of BiF3/C cathode via adding amorphous AlPO4 for lithium-ion batteries
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通过添加非晶态 AlPO4 改善锂离子电池 BiF3/C 正极的电化学性能
DOI：
10.1016/j.electacta.2013.03.168
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发表时间：
2013-07-15
影响因子：
6.6
通讯作者：
Liu, Xue
中科院分区：
文献类型：
--
作者：
Hu, Benan;Wang, Xianyou;Liu, Xue
即使在放电电压超过2V时，基于锂离子电池转化反应的高压BiF3电极也无法避免阴极反应导致的基于环状碳酸酯的固体电解质界面（SEI）的形成。SEI的形成对BiF3的电化学性能具有相当大的负面影响。为了限制这种副反应效应，通过固相研磨工艺成功制备了具有不同量非晶AlPO4的BiF3/C/AlPO4复合材料。通过粉末X射线衍射（XRD）、扫描电子显微镜（SEM）、透射电子显微镜（TEM）、选区电子衍射（SAED）、傅里叶变换红外光谱（FT-IR）和X射线光电子能谱（XPS）对BiF3/C/AlPO4复合材料的结构和形貌进行表征。通过恒电流充电/放电、循环伏安法（CV）和电化学阻抗谱（EIS）测量研究了BiF3/C/AlPO4复合材料的电化学性能。结果表明，非晶AlPO4的加入并没有改变BiF3的体结构，BiF3/C/AlPO4复合材料仍然保持BiF3的面心立方结构。此外，结果进一步证实了Bi纳米金属表面会形成SEI膜，且非晶AlPO4的量与SEI的形成密切相关。随着用量的增加，SEI形成逐渐消失。当无定形 AlPO4 的量增加到 15.0 wt.% 时，SEI 的形成得到有效限制。其中，AlPO4含量为15.0 wt.%的BiF3/C/AlPO4复合材料表现出最高的首次放电容量263.6 mAh g(-1)、最低的不可逆容量45.1 mAh g(-1)、最好的倍率性能和循环稳定性。 (c) 2013 Elsevier Ltd. 保留所有权利。
High voltage BiF3 electrode based on conversion reaction for lithium ion batteries is not immune to cyclic carbonate-based solid electrolyte interface (SEI) formation by a cathodic reaction even when discharge voltage exceeds 2 V. The SEI formation has considerable negative effect on the electrochemical properties of BiF3. To restrict this side-reaction effect, the BiF3/C/AlPO4 composites with different amount of amorphous AlPO4 have been successfully prepared by solid state milling process. The structure and morphology of BiF3/C/AlPO4 composites are characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). The electrochemical performance of BiF3/C/AlPO4 composites has been studied by galvanostatic charge/discharge, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements. The results show that the addition of amorphous AlPO4 does not change the bulk structure of BiF3, and the BiF3/C/AlPO4 composites still keep face-centered cubic structure of BiF3. Besides, the results further confirm that SEI film will be formed on the Bi nanometal surfaces, and the amount of amorphous AlPO4 is closely relevant with the SEI formation. With the increase of the amount, the SEI formation vanishes gradually. When increasing the amount of amorphous AlPO4 to 15.0 wt.%, the SEI formation is restricted effectively. Particularly, the BiF3/C/AlPO4 composite with 15.0 wt.% AlPO4 exhibits the highest initial discharge capacity of 263.6 mAh g(-1), the lowest irreversible capacity of 45.1 mAh g(-1), the best rate capability and cycling stability. (c) 2013 Elsevier Ltd. All rights reserved.