Perovskite-type RCoO3 (R = Pr, Eu, Gd) nanofibers for supercapacitor electrodes and antiferromagnet

Rare earth orthocobaltates nanofibers (PrCoO3, EuCoO3, and GdCoO3) were prepared by a simple electrospinning method coupled with calcination. The PrCoO3, EuCoO3, and GdCoO3 nanofibers have orthorhombic perovskite structure. The fabricated electrodes presented the typical pseudocapacitive characteristics, which originated from the reversible redox reactions of Co2+/Co3+ and Fe(CN)63−/Fe(CN)64−. At 1 A g−1, the specific capacitances of the PrCoO3, EuCoO3, and GdCoO3 nanofibers were 119, 133, and 196 F g−1, respectively. The electrochemical characteristics of the PrCoO3, EuCoO3, and GdCoO3 nanofibers exhibited favorable specific capacitance, good long-term cycling stability, and high coulombic efficiency, proving the possible application into energy storage devices. PrCoO3 and EuCoO3 nanofibers exhibited a magnetic state transition from paramagnetic to antiferromagnetic state. GdCoO3 nanofibers showed a paramagnetic ordering at high temperature. The cooperation of the R3+ ions and the Co2+ ions contributed to the magnetism of rare earth orthocobaltates nanofibers. The antiferromagnetic behaviors of the fabricated samples confirm the potential application into spin-electronic devices.