Rational designing carbon nanotubes incorporated oxygen vacancy-enriched bimetallic (Ni, Co) oxide nanocages for high-performance hybrid supercapacitor

Abstract

NiCo bimetallic oxide with low cost and high theoretical capacity is the candidate for high-performance supercapacitor electrodes, but the low conductivity and short cycle life of oxides have hindered their development. Herein, we designed a novel strategy for the fabrication of carbon nanotubes (CNT) incorporated oxygen vacancy (OV) NixCo1-xO nanocages for high performance supercapacitor. The existing oxygen vacancy in OV-NixCo1-xO nanocage changes the electronic environment on the crystal surface and provides more active sites, leading to the enhanced electrical conductivity together with CNT and capture capability for OH–. This CNT/OV-NixCo1-xO composite achieves high capacitance of 1400.7 F g−1 at the current density of 1 A g−1. When assembled a hybrid supercapacitor device of CNT/OV-NixCo1-xO//activated carbon, it exhibits an excellent energy density of 52.7 Wh kg−1 at a power density of 800 W kg−1. Besides, the device exhibited a capacity retention of 85.7 % over up to 10,000 cycles. This work provides a feasible strategy for surface vacancy regulation of Prussian blue derivatives used in high performance supercapacitor.