A green and high energy density asymmetric supercapacitor based on ultrathin MnO2 nanostructures and functional mesoporous carbon nanotube electrodes

Hao Jiang; Chunzhong Li; Ting Sun; Jan Ma

doi:10.1039/c1nr11542a

A green and high energy density asymmetric supercapacitor based on ultrathin MnO2 nanostructures and functional mesoporous carbon nanotube electrodes

Nanoscale. 2012 Feb 7;4(3):807-12. doi: 10.1039/c1nr11542a. Epub 2011 Dec 12.

Authors

Hao Jiang¹, Chunzhong Li, Ting Sun, Jan Ma

Affiliation

¹ Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science & Technology, Shanghai, 200237, China.

PMID: 22159343
DOI: 10.1039/c1nr11542a

Abstract

A green asymmetric supercapacitor with high energy density has been developed using birnessite-type ultrathin porous MnO(2) nanoflowers (UBMNFs) as positive electrode and functional mesoporous carbon nanotubes (FMCNTs) as negative electrode in 1 M Na(2)SO(4) electrolyte. Both of the electrode materials possess excellent electrochemical performances, with high surface areas and narrow pore size distributions. More significantly, the assembled asymmetric supercapacitor with optimal mass ratio can be cycled reversibly in the high-potential range of 0-2.0 V and exhibits an excellent energy density as high as 47.4 W h kg(-1), which is much higher than those of symmetric supercapacitors based on UBMNFs//UBMNFs and FMCNTs//FMCNTs supercapacitors. Furthermore, our asymmetric supercapacitor (ASC) device also exhibits a superior cycling stability with 90% retention of the initial specific capacitance after 1000 cycles and stable Coulombic efficiency of ~98%. These intriguing results exhibit great potential in developing high energy density "green supercapacitors" for practical applications.