纳米α-MnO_2/活性炭混合超级电容器的性能

Hybrid supercapacitor with nanosized α-MnO_2/activated carbon as electrodes

研究了以纳米α-MnO2和活性炭(AC)为电极材料的超级电容器,分别对纳米α-MnO2的制备、电解液浓度的影响进行了研究,组装了MnO2/KOH/MnO2、AC/KOH/AC、MnO2/KOH/AC三种类型的模拟电容器,用循环伏安、恒流充放电、自放电以及时间常数法对电极和电容器进行性能测试,发现当电解液KOH浓度为7mol.L-1时,混合超级电容器性能最佳,α-MnO2单电极比电容可达237F.g-1,混合电容器工作电压高达1.5V,并且具有良好的大电流放电性能和较好的循环寿命,实验还表明混合超级电容器具有极低的自放电率.

The supercapacitor using nanosized α-MnO2 and activated carbon as electrode materials was developed, and the synthesization of nanosized α-MnO2 and the effect of the concentration of electrolyte on the performance were studied in detail. Three kinds of supercapacitors, MnO2/KOH/MnO2, AC/KOH/ AC and MnO2/KOH/AC, were prepared. Cyclic voltammetry （CV）, galvanostatic charge-discharge and time constant technology were used to study the performance of the electrodes and the supercapacitors. The results showed that excellent performance of the electrods was found when the concentration of KOH solution was 7 mol · L^-1. Specific capacitance of α-MnO2 could reach a value of 237 F · g^-1. The supercapacitors with AC electrode as negative electrode and asymmetric configuration had better characteristics than the ones composed of two identical AC or MnO2 electrodes. The operating voltage of α-MnO2/KOH/ AC hybrid super-capacitor was 1.5 V and had low self discharge rate.