An oxygen-deficient cobalt-manganese oxide nanowire doped with P designed for high performance asymmetric supercapacitor

ABSTACT Transition metal oxides (TMOs) have poor electronic conductivity and insufficient electrochemical active sites, which prevent them from being widely applied in high-performance supercapacitors. Herein, a phosphorus-doped cobalt-manganese oxide nanowires electrode with rich oxygen vacancies (P-Co2MnO4-x) is successfully synthesized by two simple methods (hydrothermal and calcination). The oxygen vacancies formed in high temperature sintering increase the conductivity of the original electrode materials. In addition, trace doping of P atoms in Co2MnO4-x can improve the redox kinetics and provide more electrochemical active centers for electrode materials. As a result, the optimized P-Co2MnO4-x nanowires electrode delivers an ultrahigh mass specific capacity of 838 F g−1 at 1 A g−1, and a super cycling stability (80.3% capacitance retention after 10000 cycles). A hybrid supercapacitor assembling with P-Co2MnO4-x electrode exhibits a supernal energy density of 25.18 Wh kg−1 along with a remarkable power energy of 800.07 W kg−1. The introduction of double defects into binary cobalt-manganese oxide is shown to be resultful in improving the electrochemical performance of materials in this study. Moreover, this research also provides a novel way of thinking for the further study of defect engineering.