Low cost flexible 3-D aligned and cross-linked efficient ZnFe2O4 nano-flakes electrode on stainless steel mesh for asymmetric supercapacitors

A simple and economic approach for growth of 3-D aligned and cross-linked ZnFe2O4 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 ZnFe2O4 nano flake thin film (ZnFe2O4/FSSM-300) as an anode in combination with Ni(OH)(2)/FSSM-300 as a cathode was used as an asymmetric supercapacitor. Furthermore, ZnFe2O4 nano-flakes were also grown on FSSM with a different mesh and designated as ZnFe2O4/FSSM-200, ZnFe2O4/FSSM-250 and ZnFe2O4/FSSM-300 for investigating the effect of mesh size on the morphology formation and their electrochemical performance. Amongst the samples, ZnFe2O4/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 ZnFe2O4/FSSM-250 (545 F g(-1) at 1 mA cm(-2), 70% retention), ZnFe2O4/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)).