A Cr₂O₃/MWCNTs composite as a superior electrode material for supercapacitor

It has been a challenge to achieve a good capacitive performance for Cr-based oxides, and only few studies have been reported on these oxides. Herein, a composite of chromium oxide (Cr₂O₃) and multi-walled carbon nanotubes (MWCNTs) was prepared by a simple hydrothermal procedure followed by thermal decomposition. The Cr₂O₃ nanoparticles were evenly decorated on the surface of MWCNTs. The prepared Cr₂O₃/MWCNTs composite exhibited superior electrochemical performance in a 1 M KOH electrolyte, i.e., 257 F g^-1 at the current density of 0.25 A g^-1, and the capacity fade was only 12% after 3000 cycles. In addition, the Cr₂O₃/MWCNTs//AC asymmetric capacitor has high energy density (15.2 W h kg^-1 at 266 W kg^-1). The abovementioned results for the first time indicate the potential application of Cr₂O₃ as an electrode material for supercapacitors.