Facile synthesis of Pr-doped Co3O4 nanoflakes on the nickel-foam for high performance supercapacitors

Abstract

In recent decades, one of the biggest challenges is finding an electrode materials with high performance for the high supercapacitor having energy density and long cycle life. Meantime, Rare earth has attracted much attention in the energy storage applications for it unique properties. Herein, we synthesized the Pr2O3 doped Co3O4 nanoflakes (Pr2O3/Co3O4) grown on the nickel foam by simple hydrothermal synthesis and calcination process for supercapacitor applications. The synthesized nanoflakes regarded as unbonded and conductor-free electrode materials have excellent electrochemical performance in supercapacitors. Dramatic improvement in the rate capacity of the Co3O4 nanoflakes is achieved by doping Pr2O3. The as-prepared Pr2O3/Co3O4 electrode presents a remarkable specific capacitance of 640 C g−1 at 2 A g−1 and excellent capacitance retention of 98% after 5000 charge-discharge cycles at 10 A g−1. Moreover, an asymmetric capacitors assembled (ASC) is composed of the battery-type Pr2O3/Co3O4 electrodes and the capacitance of activated carbon (AC) electrodes, in which the Pr2O3/Co3O4 electrode as a positive and activated carbon (AC) as a negative electrode, showing a maximum energy density of 42.3 Wh kg−1 at power density of 240 W kg−1 and better capacity retention of 88% when maximum current density at 1 A g−1 after 5000 cycles. The remarkable electrochemical performance of the as-fabricated Pr2O3/Co3O4 nanoflakes electrode material indicates the promising prospects in supercapacitors.