Facile Synthesis of Single- and Multi-Layer Graphene/Mn₃O₄ Integrated 3D Urchin-Shaped Hybrid Composite Electrodes by Core-Shell Electrospinning

Three-dimensional (3D) urchin-shaped free-standing composite electrodes were produced by the integration of single- and multi-layer graphene and manganese oxide in a step-wise procedure. The strong interactions between the components were confirmed by spectroscopic characterization techniques. The influence of single- and multi-layer graphene on the electrochemical performance of composite electrodes was investigated in detail. Single-layer graphene with more oxygen functional groups showed better interfacial interactions between each component due to the exfoliated structure. The electrode containing single-layer graphene exhibited 28% higher specific capacitance of 452 F/g at a scan rate of 1 mV/s compared to that of multi-layer graphene. After 1000 cycles of charging-discharging, single platelet graphene-based electrode with a high capacitance retention of 89% showed improved synergistic effects by the combination of conductive PANI, single platelets graphene, and manganese oxide. This study indicated the importance of intercalated and exfoliated state of graphene in electrochemical behavior of supercapacitor electrodes.