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

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.