【摘要】 FeS₂的理论比容量很高,但由于其室温循环可利用性很差,使其工业化应用受到了很大限制。CuFeS₂具有较好的光、电和磁性质,但其室温电导率较低,不能满足实际应用的要求。利用溶剂热方法对CuFeS₂进行碳包覆,以期改善Li/CuFeS₂电池的室温电化学性能。研究结果表明,碳包覆使CuFeS₂颗粒尺寸明显减小并且颗粒边缘更加圆滑。以其为活性物质装配锂电池,与CuFeS₂的放电曲线类似,分别在1.6和1.4 V出现两个放电平台。在60 mA/g电流密度下,首次放电比容量达到了563.2 mAh/g,接近CuFeS₂的理论比容量（583 mAh/g）,比未包覆的CuFeS₂提高了约9.1%。在1 200 mA/g的高电流密度下,碳包覆CuFeS₂电极首次放电比容量达到了432.5 mAh/g,30次循环后的放电比容量仍可达到130 mAh/g,远高于纯CuFeS₂的比容量。循环伏安特性曲线以及交流阻抗谱测试结果表明,碳包覆使CuFeS₂电极的极化程度减小,电池的内阻下降,这从另一角度证实了碳包覆对CuFeS₂电化学性能的改善。更多还原

【Abstract】 FeS₂ has high specific capacity; however, poor cyclic performance greatly limits its application in industry. CuFeS₂ has good optical, electric and magnetic properties, but its low conductivity at room temperature is still difficult to meet the needs of application. The carbon coating was used by solvothermal process to improve the electrochemical properties of CuFeS₂. The results prove that carbon-coating changes the CuFeS₂ from hexagonal plate-like particles to smaller ones.Charge-discharge measurements prove that the carbon-coated CuFeS₂ presents two discharge plateaus at 1.6 and 1.4 V,respectively, and its initial discharging specific capacity is about 563.2 mAh/g at a current density of 60 mA/g. This value is9.1% higher than that of the uncoated CuFeS₂. At a current density of 1 200 mA/g, the initial discharging capacity of the carbon-coated CuFeS₂ is about 432.5 mAh/g, and the discharging specific capacity is 130 mAh/g after 30 cycles. Cyclic voltammograms and AC impedance spectra reveal that carbon coating can reduce internal resistance and improve the electrochemical properties of CuFeS₂.更多还原