FeS_2/RGO纳米复合材料的制备及热电池放电性能

Hydrothermal Synthesis of FeS_2/Reduced Graphene Oxide Nanocomposite with Enhanced Discharge Performance for Thermal Battery

以氯化亚铁、硫代硫酸钠和氧化石墨烯(GO)为原料,采用水热法制备FeS_2/还原氧化石墨烯(RGO)纳米复合材料,并采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、激光粒度分布仪和差热分析仪(DTA)等对FeS_2/RGO复合材料进行了表征。结果表明,在水热反应过程中加入GO可以防止FeS_2颗粒的团聚,使FeS_2形成疏松的球状颗粒。采用Li Cl-KCl电解质,在450℃以100m A/cm^2电流密度放电时,截止1.5 V时,FeS_2/RGO比容量为314.9 mAh/g,较FeS_2高65.6 mAh/g;采用Li F-Li Cl-Li Br电解质,在500℃以100 mA/cm^2电流密度放电,截止1.5 V时,FeS_2/RGO放电比容量为302.3 mAh/g,较FeS_2高29.8 mAh/g。与FeS_2相比,加入石墨烯提高了正极材料的导电性,单体电池在放电过程中极化电阻相对较小,使得FeS_2/RGO复合材料表现出较高的放电比容量。

FeS2/reduced graphene oxide（RGO） composites were prepared through a facile hydrothermal method using FeCl2, Na2S2O3 and graphene oxide（GO） as the starting materials. X-ray diffractometer（XRD）, scanning electron microscope（SEM）, laser particle size distribution analyzer, and differential thermal analyzer（DTA） were used to characterize the prepared nanocomposites. The results show that graphene oxide prevents the aggregation of FeS2 particles during the hydrothermal synthesis, and make FeS2 form loose spherical particles. FeS2/RGO exhibits a high specific capacity of 314.9 m Ah/g with a cut-off voltage of 1.5 V at constant current density of 100 m A/cm^2 and temperature of 450℃ in Li Cl-KCl melt, which is 65.6 m Ah/g higher than that of FeS2. FeS2/RGO exhibits a high specific capacity of 302.3 mAh/g with a cut-off voltage of 1.5 V at constant current density of 100 m A/cm^2 and temperature of 500℃ in Li F-Li Cl-Li Br melt, which is 29.8 m Ah/g higher than that of FeS2. In contrast with FeS2, the conductivity of the FeS2/RGO cathode material is improved, the resistance of the single cell is relatively lower during discharge process, thus FeS2/RGO cathode has a better battery discharge capacity.