Polypyrrole and activated carbon enriched MnCo₂O₄ ternary composite as efficient electrode material for hybrid...

The development of proficient electrode materials is one of the major tasks faced by modern techniques for energy storage. Integrating different materials with synergistic effects can be a valuable strategy for designing storage devices with high capacity and energy density. The spinel manganese cobaltite (MnCo₂O₄) is an outstanding candidate for supercapacitors owing to its remarkable pseudocapacitive behavior. However, it suffers from low electric conductivity and limited cyclic stability. To overcome its limitations, activated carbon with superior cyclic stability and polypyrrole with high electric conductivity can be incorporated in MnCo₂O₄. The synergistic effect of these components offers high capacitance, better conductivity, and superior cyclic performance to the ternary composite. Herein, the MnCo₂O₄/AC/PPY ternary composite has been synthesized by a facile approach. The optimized ternary composite (MAP-20) exhibited a wonderful capacitance of 945.77 F g^-1 at five mV s^-1 compared to pristine MnCo₂O₄ (254.98 F g^-1). The real-time applicability of the optimized composite was tested with asymmetric device configuration. The asymmetric device with MAP-20 and MnO₂/AC electrodes exhibited a wonderful E_d of 88.12 W h kg^-1 (P_d ∼ 1.6 kW kg^-1). The asymmetric device also exhibited excellent cyclic performance of 89.68% for 10 000 cycles. Further, the real-time applicability of the device was tested by illuminating a 39 red LED panel. Three asymmetric cells connected in series illuminated the panel for about 45 minutes. All these results suggest that the synergistic integration of various efficient electrode materials leads to enhanced electrochemical performance of supercapacitors.