FeS2-CoS2多相硫化物正极材料电化学性能研究

Study of Electrochemical Property of FeS2-CoS2 Multiphase Sulfide Cathode Materials

采用物理机械混合法制备了热电池用FeS2-CoS2多相正极材料,并探索了Fe、Co含量对热电池放电性能的影响。利用X射线衍射、扫描电镜获得混合硫化物的成分、结构以及表面形貌。实验结果表明:与单相正极材料相比,Fe/Co复合材料不仅保持了FeS2高电压的优势,又在一定程度上延长了热电池放电时间;扫描电镜结果显示正极材料放电前后的形貌发生了变化,Li+通道随着反应的进行被产物覆盖而减少;当Fe/Co比为1∶4和1∶0.25时,单体电池放电的最高电压分别为1.67 V和1.72 V,且当截止电压为1.25 V时,放电比容量分别为250.7 mA·h/g和167.1 mA·h/g,高于其他比例的多相硫化物。

FeS2-CoS2 multiphase cathode materials for thermal battery were prepared by physical-mechanical mixing method,and the effects of iron and cobalt contents on the electrochemical property of the thermal battery were discussed.The component content,microstructure and surface morphology of mixed disulfide are analyzed by using X-ray diffraction(XRD)and scanning electron microscopy(SEM).Compared with the single-phase sulfide material,the iron-cobalt composite material not only maintains its high voltage,but also prolongs the discharge duration.SEM experimental result shows that the morphology of cathode material is changed after discharging.Since the lithium-ion channels are covered with the products during the reaction process,the channels are decreased.When the ratios of iron to cobalt are 1∶4 and 1∶0.25,the maximum discharge voltages of a single battery are 1.67 V and 1.72 V,respectively.Meanwhile,the specific capacity of the single battery is 250.7 mA·h/g and 167.1 mA·h/g when the cut-off voltage is 1.25 V,which is higher than that of other multiphase sulfide materials.