尖晶石LiMn2O4和LiCoO2与电解液的相容性

研究锂离子电池正极活性材料尖晶石LiMn2O4和LiCoO2与6种电解液充、放电时的相容性。用X射线衍射检测自制的LiCoO2试样和尖晶石LiMn2O4试样的结构；用粉末微电极循环伏安法测定6种电解液在导电剂乙炔黑表面的氧化电位；将制得的尖晶石LiMn2O4试样和LiCoO2试样在上述电解液中进行恒电流充放电实验。结果表明：充电至高电位3．3～4．3V（vs Li／Li^＋）时，如果正极活性材料表面与电解液发生不可逆反应并在其上覆盖一薄层电子不可导的钝化膜，则将导致活性材料的充、放电效率降低，放电容量减少，即正极活性材料与电解液的相容性差；反之，则相容性好；尖晶石LiMn2O4与上述6种电解液的相容性都很好，普适性强；LiCoO2与上述6种电解液的相容性差别较大，呈选择性。

Compatibilities of electrolytes with spinel LiMn2O4 and LiCoO2

The compatibilities of six kinds of electrolytes with positive electrode active materials spinel LiMn2O4 and LiCoO2 were studied. The structures and properties of the spinel LiMn2O4 and LiCoO2 prepared were detected by XRD. The oxidation potentials of the above electrolytes on the surface of the conductive reagent, acetylene black were determined by microelectrode cyclic voltammetry experiments. The galvanostatic charge-discharge experiments of the spinel LiMn2O4 and LiCoO2 were carried out in the electrolytes. The results show that if the irreversible oxi- dation occurs on the interface between the positive electrode active material and the electrolyte, and a thin electronnonconductive passivated film covers on it, both the charge-discharge efficiency and the discharge capacity of the positive electrode active material will decrease. This means that the compatibility of the electrolyte with the positive electrode active material is bad, conversely the compatibility is good. The compatibilities of the above electrolytes with the spinel LiMn2O4 are all very good. The adaptability of spinel LiMn2O4 to electrolytes is excellent, while the compatibilities of the above electrolytes with LiCoO2 are quite different. The adaptability of sample LiCoO2 to electrolytes is selective.