Binder-free oxygen-vacancy-rich MnCo2O4.5 highly crystalline porous nanosheets directly grown on carbon cloth were successfully prepared via a time-saving microwave-assisted hydrothermal route. With the assistance of microwave, the ultrathin porous nanosheets structure, accompanied by rich oxygen vacancies in MnCo2O4.5, presents abundant interspace and pores with good conductivity, resulting in a high specific capacity (522.7 C g−1 at 1 A g−1) and satisfactory long-term stability (87.6 % capacity maintenance after 5000 cycles at 10 A g−1). More importantly, the stable potential window of the obtained MnCo2O4.5 electrode is extended to 1.05 V (0–1.05 V vs. Hg/HgO), surpassing the commonly reported potential window of MnCo2O4.5-based electrode materials, which typically falls below 0.75 V. Moreover, the assembled MnCo2O4.5/a-CC//AC all-solid-state asymmetric supercapacitor exhibits a wide stable voltage of 2.05 V, high energy density of 30.8 Wh kg−1 at 1025 W kg−1, with excellent long-term endurance (83.7 % capacity preservation after 6000 cycles at 5 A g−1) and mechanical flexibility. These results demonstrate the promising application of microwave-assisted oxygen-deficient MnCo2O4.5 in flexible wearable devices.