Preparation And Properties Of Cathode Materials For Lithium Primary Batteries

Lithium primary battery has the advantages of good storage,stable discharge performance,high energy density,easy to make a variety of specifications,easy to carry and more tolerant harsh environment and other significant advantages in military,outdoor equipment and widely used in other fields.In recent years,with the rapid development of power batteries,a battery exploration research is also much attention.In this paper,the LiCoO₂ powder is charged by electrochemical method,which is converted into Li_xCoO₂ by electrochemical method.The structure,composition,morphology and thermal stability of the prepared powder are analyzed.The Li_xCoO₂ was used as the cathode material to assemble the button cell to study its discharge performance.Li_xCoO₂ was prepared by using LiCoO₂ as the positive electrode and the metal lithium as the negative electrode material,adding the separator and the electrolyte,the adhesiveness and the electrodeless film,and then charging the Li_xCoO₂.The morphological analysis of the positive powder showed that the particle size and surface morphology did not change obviously before and after the lithium removal,and the dispersion of the powder was also good.The structure of the powder was analyzed,and some of the crystal diffraction peaks shifted to the left.Indicating that the Li_xCoO₂ crystal structure changes,after a part of Li⁺come off,the crystal c axis expansion,but the overall hexagonal layered structure unchanged.The loss rate of Li_xCoO₂ powder under argon atmosphere is less than 1%,which indicates that the Li_xCoO₂ has no thermal decomposition and good thermal stability in the use range?room temperature¹00??.The influence of the type and proportion of the conductive agent was discussed,and the mass ratio of Li_xCoO₂ to the conductive agent was 9:1.The discharge performance of the positive powder was larger at different magnification current?0.2C?small magnification discharge more stable,the polarization is smaller,the discharge of the specific capacity of100mAh/g,?1C?large magnification current discharge,the discharge faster,the discharge instantaneous power,the discharge of the specific capacity is about 90mAh/g.In order to improve the discharge performance of the positive powder,the use of high voltage electrolytic solution can increase the discharge medium pressure and discharge specific capacity,up to 113.1 mAh/g at 1C magnification current.The process parameters were as follows:the mass ratio of Li_xCoO₂ positive powder,conductive agent and adhesive PVDF was 18:2:1,the thickness of the pole piece was control in 150?m,the first 60?blast drying4 h and then vacuum 120?dry 2 h,button cell sealing pressure control in about 1MPa.The results show that the process has good stability,good discharge effect and discharge capacity of about 116 mAh/g.The influence of the content on the charging process and the discharge process was studied.The results showed that the lower content of the conductive additive had no obvious effect on the charging process and the discharge performance.