Low cost flexible 3-D aligned and cross-linked efficient ZnFe ₂O ₄ nano-flakes electrode on stainless steel mesh for asymmetric supercapacitors

Abstract

3-D ZnFe ₂O ₄/FSSM-300 nano-flakes on flexible stainless steel mesh as anode and Ni(OH) ₂/FSSM-300 as cathode was used to fabricate an asymmetric supercapacitor.

Abstract

A simple and economic approach for growth of 3-D aligned and cross-linked ZnFe ₂O ₄ nano-flakes on a flexible stainless steel mesh (FSSM) substrate (300 mesh) using a rotational chemical bath deposition technique for fabricating efficient asymmetric supercapacitors is reported. The prepared ZnFe ₂O ₄ nano-flake thin film (ZnFe ₂O ₄/FSSM-300) as an anode in combination with Ni(OH) ₂/FSSM-300 as a cathode was used as an asymmetric supercapacitor. Furthermore, ZnFe ₂O ₄ nano-flakes were also grown on FSSM with a different mesh and designated as ZnFe ₂O ₄/FSSM-200, ZnFe ₂O ₄/FSSM-250 and ZnFe ₂O ₄/FSSM-300 for investigating the effect of mesh size on the morphology formation and their electrochemical performance. Amongst the samples, ZnFe ₂O ₄/FSSM-300 exhibited excellent supercapacitive properties, such as a higher specific capacitance (1625 F g ⁻¹ at 1 mA cm ⁻²) and excellent cycle stability (8000 cycles, 97% retention), which was marginally higher than ZnFe ₂O ₄/FSSM-250 (545 F g ⁻¹ at 1 mA cm ⁻², 70% retention), ZnFe ₂O ₄/FSSM-200 (241 F g ⁻¹ at 1 mA cm ⁻², 56% retention) and other earlier reported ferrites. In addition, the fabricated asymmetric pseudocapacitor device delivered better performance with high specific capacitance (118 F g ⁻¹ at 5 mA cm ⁻²), excellent cycle stability (8000 cycles, 83% capacitance retention) and high energy density (42 W h kg ⁻¹) even at higher power density (5 kW kg ⁻¹).