Fabrication of robust Fe2O3@NiCo2O4 core-shell composite with spikey surface for high-performance asymmetric solid-state supercapacitor

The need for a cost-effective and efficient energy storage system instigates researchers to develop emerging electrode materials for energy storage devices. The α-Fe2O3-based electrode material for supercapacitor application has received interest due to its good electrochemical performance, high mechanical strength, corrosion resistance, low cost, and abundant availability. This work develops a cost-effective, robust Fe2O3@NiCo2O4 core-shell composite with spikey surface via a facile hydrothermal strategy for high-performance electrode material for supercapacitors. The spikes of Fe2O3 are developed on NiCo2O4 to collaborate in a more accessible surface area, with robust morphological stability throughout electrochemical performances. The Fe2O3@NiCo2O4 core-shell composite exhibits a high specific capacity of 364 C g−1 at the scan rate of 5 mV s−1 and 81% cycling stability up to 10,000 successive charge-discharge cycles at the current density of 15 A g−1. Moreover, an asymmetric solid-state supercapacitor (ASSC) device was fabricated using Fe2O3@NiCo2O4 composite as a positive electrode and commercially purchased activated carbon as a negative electrode assembled via PVA/KOH gel electrolyte. The fabricated device offers a significant energy density of 31.7 W h Kg−1 at a power density of 700 W Kg−1. The ASSC exhibits excellent capacitance retention of 90% with ultra-high coulombic efficiency of 99.7% up to 10,000 GCD cycles. The ASSC can illuminate the red and yellow LED light. This work indicates that a robust Fe2O3@NiCo2O4 core-shell composite can be an economic strategy for fabricating high-performance practical supercapacitor applications.