Morphology-controlled synthesis of La[Fe(CN)6] and the porous erythrocyte-like derivant applied for high-performance supercapacitors

Abstract

LaFe(CN) 6 with different morphologies were prepared via controlling the composition of mixed solvent which effecting the supersaturation of K 3 Fe(CN) 6 , and the structural evolution of the LaFe(CN) 6 was further explored. The porous LaFeO 3 with the same shape was obtained by calcining the LaFe(CN) 6 at 500 °C, exhibiting high performance for battery-type supercapacitor. • Supersaturation controls the morphology evolution of La-Fe PBA. • The uniform-sized La-Fe PBA with an erythrocyte-like structure was explored. • Erythrocyte-like LaFeO 3 exhibits superior stability and electrochemical performance. The porous electrodes derived from Prussian blue analogs (PBAs) show high specific capacity and superior energy densities in supercapacitors due to their tunable chemical compositions, open three-dimensional network framework and large surface area. In this work, La-Fe PBA with different morphologies is prepared at mild conditions via controlling the composition of mixed solvent and the structural evolution of the La-Fe PBA is further explored. The solubility of K 3 [Fe(CN) 6 ] and the influence of ethanol on the crystal growth is used to control the synthesis of La-Fe PBA. Four different morphologies of La-Fe PBA, such as chamfered hexagonal bipyramid microcrystals, hexagonal flakes, erythrocyte-like microstructure and small flakes, are successfully synthesized by changing the ethanol/water ratio of mixed solvent. The porous LaFeO 3 with the same shape is obtained by calcining the La-Fe PBA at 500 °C, which is subsequently employed as electrodes for battery-type supercapacitor. The erythrocyte-like LaFeO 3 shows remarkable specific capacity (330 C g −1 ) at 1 A g −1 , energy density (23.8 Wh kg −1 ) and power density (400 W kg −1 ) at 1 A g −1 . This work could provide a porous material for high-performance supercapacitors as well as an exciting strategy to develop and design materials with specific morphology.