A comparative study of high density Vertically Aligned Carbon Nanotubes grown onto different grades of aluminum – Application to supercapacitors

Abstract

Vertically aligned carbon nanotubes (VACNT) have received extensive attention as electrode materials for supercapacitors owing to their superior features: no formatting or binder needed, anisotropy. They can be obtained by aerosol-assisted Catalytic Chemical Vapor Deposition (CCVD), a cost-effective and roll-to-roll compatible process, directly onto aluminum current collectors by lowering their growth temperature. In this paper, a comparative study of high density VACNT grown onto different grades of aluminum collectors is performed. Influence on electrochemical performances of carpet thickness up to 170 μm and VACNT volumetric density ranging from 70 to 350 mg/cm3 is evaluated. VACNT electrodes exhibit high areal capacitance up to 360 mF/cm2 and 25 F/cm3 and average gravimetric capacitance is 45 F/g. At high scan rate volumetric density has low impact while increasing height of VACNT limit performances. Symmetrical supercapacitor based on VACNT/Al electrodes assembled in coin-cell exhibits high energy and power density with high potential difference of 2.7 V and great energy retention capacity (90% at 13 A/g). Such results outline the benefits of the VACNT growth process directly applicable to aluminum current collector meeting industrial requirements (high purity and thin thickness) and exhibit the huge potentialities of such electrode to realize in supercapacitor applications.