Zinc ferrite nanoparticles as electrode material for supercapacitors

In the realm of sustainable and renewable nanotechnology, supercapacitors have appeared as the dominant solution for energy conversion and storage. Ferrites have been widely explored in magnetic, electronic and microwave devices, and are now being explored for applications in energy storage devices due to the possibility of achieving fast and reversible surface Faradic reactions. From this perspective, a simple and inexpensive chemical co-precipitation method was used to synthesize ultrasmall ZnFe2O4 nanoparticles (NPs). As an electrode material the ZnFe2O4 NPs show a gravimetric capacitance of 186.6 F g(-1) at a current density of 1 A g(-1) in 1 M H2SO4. Furthermore, the ZnFe2O4 NP-based electrode shows exceptional capacitive retention of 98% over 1000 cycles at a current density of 3 A g(-1). An asymmetric ZnFe2O4 NP//NiO NP device was fabricated, which achieved a power density of 302.3 W kg(-1) at a current density of 1.5 A g(-1) and an energy density of 14.85 W h kg(-1). After 1500 cycles, the device demonstrated capacity retention of 99.4% at 1.5 A g(-1) in long-term stability testing with 100% efficiency. Our study suggests that ZnFe2O4 NPs are promising as a material for future energy storage applications.