The Study On Preparation And Modification Of Multiple Disulfide Cathode Materials For Li-B Thermal Battery

Co_xNi_1-xS₂ material can not only combine the advantages of CoS₂ material with good conductivity,small self-discharge,and NiS₂ material with high discharge voltage platform and high specific capacity,but also make up for the defects of CoS₂material and NiS₂ material.It has been reported that Co_xNi_1-xS₂ is a promising cathode material for thermal battery,which has the advantages of high conductivity,high discharge voltage,stable voltage platform,and large specific capacity.The main weakness with the Co_xNi_1-xS₂ material is that it can only use in a narrow temperature range,which limits its practical application.Co_xNi_1-xS₂ material was characterize and test its discharge performance in this paper which was prepared by hydrothermal method.At the same time,there was a modified research on the deficiency of the Co_xNi_1-xS₂material.The aim of this paper is to explore the preparation process and reaction principle of Co_xNi_1-xS₂ cathode materials prepared by hydrothermal synthesis.The preparation process was studied from four aspects those are optimization of chelating agent ratio,reaction temperature,metal ion ratio,and reaction time.The phase structure and morphology were analysis by FESEM and XRD.The results show that the Co_xNi_1-xS₂material could be prepared with high purity,good degree crystallization and regular shape hollow microspheres,when the molar ratio of chelating agent to metal ions and nickel and cobalt ions are separately 0.9:0.1 and 0.1:1,the reaction temperature is150°C,and the reaction time is 24 h.The Co_xNi_1-xS₂ material prepared under this condition was discharged at 450°C,100 m A·cm^-2.The experimental data suggested that the internal resistances of the Co_xNi_1-xS₂ material was lowest,and its specific capacity was 292.7 m A·h·g^-1,which was 84.31 m A·h·g^-1 higher than that of the pure NiS₂ material and the utilization rate of active substance is 61.1%,which was 10.1%higher than that of pure NiS₂ material.The effects of drying conditions and discharge conditions on battery discharge performance were studied in this paper.The discharge test results show that the drying conditions have influence on the discharge performance of Co_xNi_1-xS₂ material.Drying in vacuum was most suitable for Co_xNi_1-xS₂ material,the optimal drying temperature is 80°C,and the optimal drying time is 6 h.The electrochemical performance was influence by discharge conditions,which shown best performance in450°C and 100 m A·cm^-2.In this paper,Co_xNi_1-xS₂ material was modified by doping carbon-based materials that Co_xNi_1-xS₂-EG and Co_xNi_1-xS₂-GNs were prepared by repeated grinding-tableting.The morphology was analysis by FESEM and electrochemical performance was analysis by discharge test.As a result,it demonstrated that carbon-based materials could be uniformly doped in Co_xNi_1-xS₂ material to form an efficient conductive network,which is conducive to the transport of electrons and ions and increases the conductivity of Co_xNi_1-xS₂ material.Added with Fe element to synthesis Fe_xCo_yNi_1-x-yS₂ by hydrothermal method,and study the change in discharge performance of Co_xNi_1-xS₂ after doped metal element.The phase structure and morphology were analysis by FESEM and XRD and electrochemical performance was analysis by discharge test.As shown in the results,the battery was performed best discharge performance when x=y=0.2.