The rational design of oxygen vacancies and electronic microstructures of electrode materials for energy storage devices still remains a challenge.Herein,we synthesize nickel cobalt-based oxides nanoflower arrays assembled with nanowires grown on Ni foam via the hydrothermal process followed annealing process in air and argon atmospheres respectively.It is found that the annealing atmosphere has a vital influence on the oxygen vacancies and electronic microstructures of resulting NiCo2O4(NCO-Air)and CoNiO2(NCO-Ar)products,which NCO-Ar has more oxygen vacancies and larger specific surface area of 163.48 m2/g.The density functional theory calculation reveals that more oxygen vacancies can provide more electrons to adsorb-OH free anions resulting in superior electrochemical energy storage perfor-mance.Therefore,the assembled asymmetric supercapacitor of NCO-Ar//active carbon delivers an excel-lent energy density of 112.52 Wh/kg at a power density of 558.73 W/kg and the fabricated NCO-Ar//Zn battery presents the specific capacity of 180.20 mAh/g and energy density of 308.14 Wh/kg.The exper-imental measurement and theoretical calculation not only provide a facile strategy to construct flower-like mesoporous architectures with massive oxygen vacancies,but also demonstrate that NCO-Ar is an ideal electrode material for the next generation of energy storage devices.