Fabrication of Nanosized Layered-MnO2/Activated Carbon Composites Electrodes for High-performance Supercapacitor
Ya Liu, Songlin Zuo, Baoshou Shen, Yongfang Wang, Haian Xia
Abstract
Layered-MnO2/activated carbon composites were prepared by simply mixing activated carbons and Mn (NO3)2 solution, followed by heat treatment at 300 °C in order to develop high-performance and cost-effective active materials for supercapacitor electrodes. The effects of the loading mass of MnO2, the surface chemistry and pore structure of activated carbons on the electrochemical performance of the composites as supercapacitor electrodes were investigated. The results show that layered α-MnO2 nanoparticles of about 20 nm were synthesized in the activated carbons prepared by K2S activation of lignin. A loading of 10 wt.% MnO2 led to a two-fold increase in the specific capacitance of the activated carbon, reaching 294 F g -1 at 5 mV s -1 in 2 M KOH. The surface chemistry and pore structures of the supporters exert a significant effect on the electrochemical properties of the composites. Moreover, the as-prepared composites as supercapacitor electrodes possess excellent cycle stability and rate capability.