Sustainable synthesis of NiCo2O4 nanorods with cellulose for high energy density asymmetric supercapacitor application

The NiCo2O4 nanorods were created using a simple, reliable, and economical cellulose-assisted green synthesis method for fabricating efficient positive electrodes for asymmetric supercapacitors. The metal (Ni and Co) ions were uniformly precipitated and delivered as nanorods with high surface area characteristics when alkali ions were added to the growing solution. The NiCo2O4 nanorods reveal a specific capacitance of 1302 F g⁻¹ at 1 A g⁻¹ along with a 70.6% rate capability at an elevated input current density of 20 A g⁻¹. Furthermore, it upholds a 92% stability feature over 5000 charge/discharge cycles at 20 A g⁻¹. The NiCo2O4//activated carbon device exhibits a 201 F g⁻¹ of specific capacitance at 1 A g⁻¹ with the enhanced energy and power density values of 71.6 W h Kg⁻¹ and 16 kW Kg⁻¹, respectively. The stability studies show 86% capacitance retention with 97% coulombic efficiency after 5000 cycles at an elevated input current density of 20 A g⁻¹. These results prove the perspective of NiCo2O4 nanorods as a favorable electrode substance for future energy storage-based applications.