High-performance asymmetric supercapacitors assembled with novel disc-like MnCoO microstructures as advanced cathode material.

Herein, porous MnCoO with disc-like (MnCoO-discs) and ring-like (MnCoO-rings) microstructures were respectively synthesized using an initial hydrothermal method at different temperatures and a calcination treatment in air. The electrochemical properties of these MnCoO materials were investigated in three-electrode and two-electrode systems, and as such, MnCoO presented a battery-like electrochemical response. The specific capacity of MnCoO-discs was determined to be 296.1C/g at 1 A/g, superior to 246.3C/g for MnCoO-rings. An asymmetric supercapacitor (ASC) was assembled with MnCoO as the cathode and activated carbon (AC) as the anode to evaluate the potential for practical application. The MnCoO-discs//AC ASC exhibited an energy density (E) of 35.8 W h kg at a power density (P) of 927.5 W kg. For the MnCoO-rings//AC ASC, an inferior E of 31.4 W h kg under 890.9 W kg was achieved. Furthermore, the two ASCs presented outstanding cyclic performance after 5000 cycles at 6 A/g. The exceptional properties of MnCoO microstructures can be applied to the assembly of ASC devices, which can have promising potential for application in electrochemical energy storage. This synthetic method is straightforward, cost-effective, and can be extended to fabricate similar electrode materials with superior electrochemical performance.