乙炔黑涂层对锂硫电池性能的影响

Effect of Acetylene Black Coating on Properties of Lithium-Sulfur Batteries

锂硫电池的循环放电稳定性较低,因此我们采用一种低成本的方法改善锂硫电池的性能,即在硫电极表面制备乙炔黑涂层并测试了材料的形貌结构及电化学性能。结果表明,在硫含量(质量分数)70%的硫-乙炔黑复合材料中,硫附着在乙炔黑颗粒表面。接着在硫电极表面制备了厚度15μm左右的乙炔黑涂层,乙炔黑涂层-硫电极的氧化反应电位低于硫电极,说明乙炔黑涂层有助于硫电极氧化反应的进行。与硫电极相比,乙炔黑涂层-硫电极活性物质的聚集程度低于硫电极,乙炔黑涂层-硫电极具有更高的放电比容量和循环放电稳定性。在150次循环充放电后,乙炔黑涂层-硫电极的放电比容量为894 mAh·g^(-1)。

Cyclic discharge stability of lithium-sulfur batteries is relatively low.Herein,a method of low cost has been adopted to improve properties of lithium-sulfur batteries.A coating of acetylene black has been prepared on the surface of sulfur electrodes.The morphology of materials and properties for batteries have been tested.The results indicate that the sulfur adheres to the surface of acetylene black particles in sulfur-acetylene black compos-ite with sulfur content(mass fraction)of 70%.The acetylene black coating with thickness of about 15μm has been prepared on the surface of lithium electrodes.The voltage for oxidation reaction of sulfur electrodes with acetylene black coating was lower than that of sulfur electrodes.Acetylene black coating is helpful in oxidation reaction of sulfur electrodes.The aggregation degree of active materials for sulfur electrodes with acetylene black coating was lower than that for sulfur electrodes.The discharge specific capacity and cyclic discharge stability of sulfur electrodes with acetylene black coating were higher than those of sulfur electrodes.After 150 cycles of charge and discharge,the discharge specific capacity of sulfur electrodes with acetylene black coating was 894 mAh·g^(-1).