正极材料不同配比对锂硫电池性能的影响机理

Influence Mechanism of Cathode Material Mixture Ratio on Lithium-sulfur Battery Performance

为研究正极材料中活性材料、导电剂、黏结剂配比对锂硫电池性能的影响,将升华硫与乙炔黑按质量比为7∶3球磨制得活性材料,然后将活性材料、导电剂、黏结剂按5种不同的质量配比制得不同的正极复合材料,观察结构和形貌并组装成电池测试性能。结果表明:7∶1∶2配比的电池在0.15C的放电倍率下,首次放电比容量最高达1019.0mAh/g,100次循环之后比容量达547.9mAh/g,容量保持率为53.7%,具有比较好的综合性能,其原因在于合理的配比使得该正极复合材料在介观上具有最佳的电子传导性,在宏观上具有足够的牢固性,机理分析对于其他微粉粘接改性也具有指导作用。

To study the influence of the ratio of active material,conductive agent and binder on performance of lithium-sulfur battery,the cathode active material was prepared by ball milling sublimed sulfur and acetylene black with mass ratio of 7∶3,cathode composite materials were prepared with five different proportions of active material,conductive agent and binder,then the structures and morphologies were observed and batteries were resembled and tested.Electrochemical tests show that the first discharge specific capacity of cathode material with proportion of 7∶1∶2 reaches1019.0 mAh/g in the current discharge rate of 0.15 C,and after 100 cycles,the specific capacity reaches 547.9 mAh/g with capacity retention rate of 53.7%,indicating the cathode material with this proportion is desirable,which is due to reasonable component ratio making this cathode composite material possess optimum mesoscopic electronic conductivity and macroscopic fastness.This mechanism can also be guidance for adhesion modification of other micro powders.