High-performance asymmetric supercapacitors assembled with novel disc-like MnCo₂O₄ microstructures as advanced...

Herein, porous MnCo₂O₄ with disc-like (MnCo₂O₄-discs) and ring-like (MnCo₂O₄-rings) microstructures were respectively synthesized using an initial hydrothermal method at different temperatures and a calcination treatment in air. The electrochemical properties of these MnCo₂O₄ materials were investigated in three-electrode and two-electrode systems, and as such, MnCo₂O₄ presented a battery-like electrochemical response. The specific capacity of MnCo₂O₄-discs was determined to be 296.1C/g at 1 A/g, superior to 246.3C/g for MnCo₂O₄-rings. An asymmetric supercapacitor (ASC) was assembled with MnCo₂O₄ as the cathode and activated carbon (AC) as the anode to evaluate the potential for practical application. The MnCo₂O₄-discs//AC ASC exhibited an energy density (E_d) of 35.8 W h kg^-1 at a power density (P_d) of 927.5 W kg^-1. For the MnCo₂O₄-rings//AC ASC, an inferior E_d of 31.4 W h kg^-1 under 890.9 W kg^-1 was achieved. Furthermore, the two ASCs presented outstanding cyclic performance after 5000 cycles at 6 A/g. The exceptional properties of MnCo₂O₄ 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.