表面活性剂对NiMn_(2)O_(4)电极材料形貌及超级电容性能的影响

Effect of Surfactant on Morphology and Supercapacitor Properties of NiMn_(2)O_(4)Electrode Material

纳米材料的形貌可以影响其电化学性能,设计形貌和尺寸可控、导电性良好的金属氧化物纳米结构是将其应用于电化学超级电容器等储能器件的一个挑战。采用共沉淀法制备了不同聚乙烯吡咯烷酮(PVP)添加量的NiMn_(2)O_(4)电极材料,研究了表面活性剂PVP的添加量(0、0.2、0.4、0.8 g)对NiMn_(2)O_(4)微观形貌及电容性能的影响。结果表明:随着PVP添加量的增加,所制备的NiMn_(2)O_(4)的微观形貌由团聚的颗粒状变为疏松的团絮状和细粉末状。当PVP添加量为0.4 g时,NiMn_(2)O_(4)的电容性能最佳,在电流密度为1 A/g时比电容为1464 F/g。添加量为0.8 g时由于过量的PVP在清洗过程中容易造成残留,在电化学测试过程中,实际参与氧化还原反应的活性物质NiMn_(2)O_(4)的量相对减小,导致NiMn_(2)O_(4)-0.8的比电容降低,在电流密度为1 A/g时的比电容为1010 F/g。

The morphology of nanomaterials can affect their electrochemical performance.It is a challenge to design metal oxide nanostructures with controllable morphology/size and good electrical conductivity for their application in electrochemical supercapacitors and other energy storage devices.NiMn_(2)O_(4)electrode materials with different amounts of polyvinylpyrrolidone(PVP)were prepared by a co-precipitation method.The effect of PVP(0,0.2,0.4,0.8 g)amount on the microstructure and capacitance properties of NiMn_(2)O_(4)was investigated.The results show that the microstructure of NiMn_(2)O_(4)changes from an agglomerated granular to loose flocculent and fine powder with the increase of PVP content.The optimum capacitance performance of NiMn_(2)O_(4)can be obtained at PVP amount of 0.4 g,and the specific capacitance of NiMn_(2)O_(4)is 1464 F/g at a current density of 1 A/g.At PVP amount of0.8 g,the excessive amount of PVP is easy to cause residue in NiMn_(2)O_(4)in the cleaning process.During the electrochemical test,the amount of active substances involved in the redox reaction is relatively reduced,leading to the decrease of the capacitance performance of NiMn_(2)O_(4)-0.8.The specific capacitance is 1010 F/g when a current density is 1 A/g.