Cycling stability of iron-based layered double hydroxide thin-films for battery-type electrode materials

The [Fe(CN)(6)](3-) intercalated Mg/Fe-LDH (LDH-CN) thin film was prepared by the intercalation-reconstruction method. By using a three-electrode system, the electrochemical performance of the film was also investigated to evaluate the cycling stability for its potential as electrode materials. The LDH-CN thin film was characterized by XRD, FT-IR, SEM and TG-DSC, indicating that the microstructure and surface morphology of the films remained basically unchanged before and after CV scanning for 50 cycles. Redox cycling of the LDH-CN/GCE kept a strong stability at 100 mV s(-1) for 50 cycles by virtue of the stability of the microstructure of the LDH-CN thin film. Such stability was likely imparted by the formation of a network of mixed-valent Fe2+/3+ oxo-bridges that underwent chemical reactions and electrochemical reactions as main capacitive charge storage ions. The LDH-CN electrode presented a maximum specific capacity of 147.2 mAh g(-1) and excellent cycle life, while it still exhibited 133.9 mAh g(-1) at the 1000th cycle at a current density of 3 A g(-1). Such a thin-film electrode made up of the LDH-CN material may be a potential economical alternative battery-type electrode material and possess electrochemical capacitors possibilities.