Preparation And Performance Of Mesoporous Materials For Supercapacitors

As a novel energy-storage system,supercapacitors with characteristics of long cycle-life and high rate charge-discharge capability can be applied in many fields.As we know the electrochemical properties of the materials of supercapacitors have a compactly relation to the sample microstructure,crystalline morphological and specific surface area.The mesoporous materials exhibit a high surface area,narrow pore size distribution,large pore volume.In this work,mesoporous NiO,MnO₂ were synthesized successfully by a soft template method and the the factors of influence on mesoporous NiO,MnO₂ synthesis and capacitive properties were also investigated.1.Mesoporous NiO obtained via a hydrothermal process(4hours and 100℃) employing 0.4g/ml sodium dodecyl Sulfate(SDS) as surfactant.The specific capacitance using the mesoporous NiO as active materials in a capacitor reached 731F/g at the current density of 0.5A/g.After 500cycles,the capacitance is still 63.8% of the first cycle.2.submicron ball shape mesoporous cobalt-nickel oxides composite were successfully synthesized using NiCl·6H₂O and CoSO₄·7H₂O.The specific capacitance and cycle-life are improved after cobalt adding.A specific capacitance of 1438 F g^-1 has been obtained at the discharge current density of 0.5A/g from the composites when NiCl·6H₂O/CoSO₄·7H₂O molar ratio is 4:1.The higher proportion of cobalt oxides is,the more exellent of the cycle performance can be demonstrated.3.Mesoporous NiO obtained using Brij35 as soft-template has the higher capacitance than using CTAB as soft-template.The specific capacitance is 467F/g and 350 F/g at current density of 0.5A/g and 1.5A/g respectively.While mesoporous NiO prepared by CTAB as soft-template has low capacitance which value is only 1/2 of the former.4.Mesoporous MnO₂ prepared by chemical coprecipitation method using sodium dodecyl Sulfate(SDS) as surfactant.The composite has the best electrochemical performance when the sodium dodecyl Sulfate(SDS) is 0.2g/ml and the template removed by solvent.The specific capacitance is 258F/g and 174 F/g at current density of 0.1A/g and 1A/g respectively. 5.The ball mesoporous MnO₂ with Flower shape were successfully prepared using CTAB as solft template.The composite has the best electrochemical performance when calcined temperature is 200℃.The specific capacitance is 195F/g at current density of 0.1A/g.