Defects rich- Cu-doped MnO2nanowires as an efficient and durable electrode for high performance aqueous supercapacitors

Defect-rich nanostructures offer unique opportunity for the fabrication of high-performance supercapacitors. In this work, a one pot and energy saving technique was designed to synthesize faulty copper doped manganese dioxide nanowires (CuxMnO2 where x = 0, 0.02, 0.05 and 0.1). The addition of copper ions enhanced the conductivity and caused a considerable rise of defects in the lattice. These defects give an abundance of active sites that play a significant role for energy storage. It is found that Cu0.05MnO2 structure exhibits enhance capacitance of 313 F g−1 at a current density of 1 A g−1 as compared to other structures with a capacitance retention of 97.3%. The fabricated asymmetric supercapacitor (CuMO-2/AC) delivers a capacitance of 97 F g−1 at 1 A g−1, achieve a maximum energy density of 53.89 Wh kg−1 at power density of 277.8 W kg−1. Moreover, the device keeps 90.3% of its preliminary capacitance after 10,000 cycles at 10 A g−1. This study reveals fresh information on the manufacturing of defect materials for energy storage applications using one pot process instead of multi steps. The results suggest that defect engineering play an important role for the development of high-performance supercapacitor for practical applications.