The Study On Preraration And Performance Of Fe-Co-Ni Ternary Disulfide Cathode Materials For Li Thermal Battery

In this paper,the research progress of Fe-Co-Ni ternary disulfide as cathode materials for thermal batteries was summarized.Co_1-x-yCo_xNi_ycathode materials system with cobalt as the main element and Fe_1-x-yCo_xNi_ycathode materials system with iron as the main element were studied respectively.The materials were characterized by XRD and SEM,and their discharge performance was tested.At the same time,the discharge mechanism of the material was preliminarily explored.The main work is as follows:Co_1-x-yCo_xNi_ycathode materials with cobalt as the main element were prepared by hydrothermal synthesis.The content of Co element accounted for more than 50%of all metal ions,Fe and Ni elements accounted for the rest part.The key parameters involved in the reaction were optimized to determine the optimal hydrothermal synthesis conditions.At the same time,the materials were characterized by XRD,SEM and discharge properties.Through the analysis of the results,EDTA-2Na was selected as the chelating agent,the molar ratio of EDTA to metal ions was 0.1:1,the reaction temperature was 170℃,and the reaction time was 24h.Co_0.8Fe_0.1Ni_0.1S₂cathode material is the best metal ion ratio in Co_1-x-yCo_xNi_ycathode material system.When the discharge cut-off voltage reaches 1.5V,the discharge specific capacity is418.20m Ah/g,and the utilization rate of active substance reaches 86.04%.At the same time,through pulse discharge test and analysis,At this time,the material internal resistance is the minimum,below 0.1Ω.Fe_1-x-yCo_xNi_ycathode material with iron as the main element was synthesized by hydrothermal synthesis method.The content of Fe element accounted for more than 50%of all metal ions,and the remaining two elements,Co and Ni,accounted for the rest.The key influencing factors in the preparation process of the materials were explored to determine the optimal hydrothermal synthesis conditions.Meanwhile,the materials were characterized by XRD,SEM and discharge properties.The results showed that the optimal material was obtained when the molar ratio of chelator to metal ions was 0.1:1,the reaction temperature was 170℃,the reaction time was 24h,and the metal ion ratio was 8:1:1.At this time,the material morphology was hollow microsphere,the discharge specific capacity reached 328.1m Ah/g and the utilization rate of active substance reached 67.5%when the discharge voltage was up to 1.5V.The discharge mechanism of the material was investigated,and the specific reactions occurred in the three discharge voltage platforms were analyzed from the discharge characteristics of three single metals,Fe,Co and Ni.And the reason for the long stable duration of the second platform is discussed in principle.The economical cost of synthetic Co_1-x-yCo_xNi_ycathode material and Fe_1-x-yCo_xNi_ycathode material were analyzed,and compared with the economical cost of cobalt disulfide material,it was found that the cost of ternary cathode material was lower than that of cobalt disulfide,and it was expected to be used as the cathode material of thermal battery in practical production.