硫源对双壳层NiCo2S4超级电容性能影响

Effect of sulfur source on performance of double-shell NiCo2S4 in supercapacitor

通过自模板法,选用硫代乙酰胺(TAA)、硫脲(TU)分别作硫源制备双壳层NiCo2S4纳米材料。其中以TAA为硫源制备的NiCo2S4表现出高的比电容(2064F/g,当电流密度为0.5A/g时),优异的倍率性能(1291F/g,当电流密度为20A/g时)和较好循环稳定性。由动力学机制分析可知,NiCo2S4-TAA表面控制电容和扩散控制电容较NiCo2S4-TU均有提升。通过实验分析可知,TAA作为硫源合成的NiCo2S4是由较小的次级颗粒聚集而成,这有利于电化学过程中电解质离子的扩散。由于较好的导电性能和离子扩散速率,NiCo2S4-TAA表现出优异的电化学性能。上述结果表明,在本实验条件下,TAA是制备NiCo2S4电容器电极材料的最佳硫源。

Double-shell NiCo2S4 were synthesized by self-template method using TAA and TU as sources,respectively.Among them,NiCo2S4 prepared by TAA delivers the highest specific capacitance(2064F/g,when the current density is 0.5A/g),better rate performance(1291F/g,when the current density is 20A/g)and good cycle stability.Further kinetic mechanism analysis shows that the surface-control and diffusion-control capacitance of NiCo2S4-TAA are both improved compared to NiCo2S4-TU.Through experimental analysis,NiCo2S4 synthesized by TAA is composed of smaller particles,which is beneficial to the diffusion of electrolyte ions in the electrochemical process.Since its good electrical conductivity and ion diffusion rate,NiCo2S4-TAA exhibits excellent electrochemical performance.Therefore,TAA is desirable sulfur source in this experiment condition.