Rational construction of multidimensional oxygen-deficient Co3O4 nanosheet/nanowire arrays as high-performance electrodes for aqueous Zn-ion batteries and asymmetric supercapacitors

Here, a surface phosphating Co3O4 electrode materials with multidimensional nanostructure and oxygen-deficient have been fabricated and applied to aqueous Zn-ion batteries and asymmetric supercapacitors. The multidimensional nanostructure is beneficial to the full contact between active materials and electrolyte. Moreover, the oxygen vacancies can enhance electrical conductivity and further increases the concentration of active sites, consequently accelerating their interface reaction activity and kinetics. Therefore, the combination of structural and compositional advantages endows the P-Co3O4 nanosheets/nanowires electrode a specific capacity of 244.9 mAh g−1 at 4 A g−1. Furthermore, the assembled P-Co3O4//Zn battery showed fascinating electrochemical performance, including a high specific capacity of 119.4 mAh g−1 at 1 A g−1 and a high energy density of 193.7 Wh kg−1 at a power density of 1.6 kW kg−1 and excellent stability of 111% capacity retention after 5000 cycles. The assembled P-Co3O4//AC ASC device also achieved an energy density of 24.87 Wh kg−1 and excellent cycle stability. Outstanding performance advantages make it possible for P-Co3O4 electrode to be applied in the fields of new energy storage devices and wearable electronic devices.