Fabrication of plate-like MnO₂ with excellent cycle stability for supercapacitor electrodes

Designing and fabricating unique nanostructured MnO₂ electrode to improve their electronic conductivity for supercapacitor application with high electrochemical performance in terms of high specific capacitance, excellent cycle stability, and good rate capability, is still a big challenge. In this work, we report novel nickel foam supported 3D plate-like MnO₂ materials as binder-free electrodes for supercapacitors. Benefiting from the unique 3D architectures, the as-obtained MnO₂ electrode possesses a high specific surface area of 60.8 m² g⁻¹, exhibits a high specific capacitance of 680.6 F g⁻¹ at a scan rate of 1 mV s⁻¹ and reveals the outstanding cycling behaviors with the capacitance retention about 91.2% and Coulombic efficiency of 100% after 4000 cycles. Furthermore, the SEM images of the MnO₂ electrode show that the plate-like structure basically remains unchanged after long-term cycles, suggesting the outstanding stability of the as-prepared electrode materials. All the above supercapacitive achievements indicate that the nickel foam supported 3D plate-like MnO₂ electrode can be a promising material for desirable supercapacitors. In addition, such unique 3D plate-like electrode architectures would be useful for other energy storage and conversion devices.