Inactive Al3+-doped La(CoCrFeMnNiAlx)1/(5+x)O3 high-entropy perovskite oxides as high performance supercapacitor electrodes

Abstract A series of high-entropy perovskite oxides (HEPOs) La(CoCrFeMnNiAl x ) 1/(5+ x ) O 3− δ ( x = 0.4, 0.5, 0.6, and 0.7) have been synthesized by coprecipitation method combined with calcination process and explored as electrodes for supercapacitors. The crystal structure, microstructure, and elemental composition of HEPOs were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and energy-dispersive X-ray spectroscopy (EDS) in detail. The electrochemical properties of HEPOs as supercapacitor electrodes were elucidated. The specific capacitances of HEPOs ( x = 0.4, 0.5, 0.6, and 0.7) are 281.84, 353.65, 325.60, and 259.30 F/g at the current density of 1 A/g, respectively. After 2000 cycles, the specific capacitances of HEPOs ( x = 0.4, 0.5, 0.6, and 0.7) remain 85.01%, 88.61%, 86.37%, and 91.25%, respectively. Such outstanding electrochemical properties can be attributed to the entropy-stabilized structure caused by mixed six cations in B-site and the Al 3+ -doping suppressing active ion aggregation during charge—discharge process. This research highlights the potential of HEPOs as electrodes for supercapacitors.