Urchin-like Ni1/3Co2/3(CO3)0.5OH·0.11H2O anchoring on polypyrrole nanotubes for supercapacitor electrodes

Abstract Metal carbonate hydroxide is a promising electrode material for advanced supercapacitors but suffers from the poor electronic conductivity. Herein, we address this issue through the in-situ formation of Ni 1/3 Co 2/3 (CO 3 ) 0.5 OH·0.11H 2 O anchoring onto the surface of polypyrrole nanotubes via a hydrothermal method. The Ni 1/3 Co 2/3 (CO 3 ) 0.5 OH·0.11H 2 O/polypyrrole nanotubes composites possess high specific surface area and electronic conductivity, resulting in large charge storage and fast charge/discharge rate. The synthesized composite electrodes exhibit a high specific capacitance of 964.8 F g −1 at 1 A g −1 and low the equivalent series resistance of 0.24 Ω. Moreover, the assembled asymmetric supercapacitors exhibit high energy density of 41.86 Wh kg −1 with a power density of 562 W kg −1 , and high power density of 11.25 kW kg −1 with an energy density of 16.97 Wh kg −1 . The capacitance retention remains 80.2% after 5000 cycles at 5 A g −1 , indicating the excellent cycling stability. The results indicate that Ni 1/3 Co 2/3 (CO 3 ) 0.5 OH·0.11H 2 O/polypyrrole nanotubes composites are a potential electrode material for high-performance supercapacitors.