MnCo2O4 hollow microspheres as a cathode of hybrid supercapacitor

Pseudocapacitors with highly reversible redox reactions and rapid electron transfer rates have been extensively investigated for energy storage. Hollow structures have attracted much attention due to their large cavity. To this end, we applied a facile method to prepare MnCo2O4 hollow spheres (HSs-MCO). The special structure exposes many active sites and abundant channels, reducing the diffusion path of ions and facilitating their rapid transport. Owing to these characteristics, HSs-MCO possesses a high specific capacity of 177 C g−1 at 1 A g−1, and it exhibits favorable stability over 10,000 charge–discharge cycles with a capacitance retention of 90.3%. Furthermore, the hybrid supercapacitor constructed with the optimal HSs-MCO cathode and activated carbon (AC) anode achieves an energy density of 13.5 Wh kg−1 at 380 W kg−1 and shows excellent stability after 10,000 cycles with a capacitance retention of 86.4%. The results presented illustrate that the excellent energy storage performance of HSs-MCO makes it a highly promising material for energy storage.