Preparation of La_0.7Sr_0.3CoO_3-δ (LSC)@MnO₂ core/shell nanorods as high-performance electrode materials for supercapacitors

Perovskite oxides have attracted significant attention as capacitor electrode materials owing to their unique physical and electronic properties. In this paper, a novel La_0.7Sr_0.3CoO_3-δ (LSC)@MnO₂ core–shell nanorod was synthesized by controlled electrospinning combined with hydrothermal synthesis. The LSC, as a typical perovskite-type material, with excellent stability and ion–electron double conductivity, can perfectly serve as conductive backbone. Grid-like MnO₂ nanosheets are grown on LSC to form a unique core/shell nanostructure, could effectively improve the electrochemical performance of MnO₂. The grid-like MnO₂ nanosheets shell significantly increase the effective area over which the reaction may take place and reduce the ion/electron transmission distance, which is beneficial in that it shifts in ions and electrons, enhancing the electrochemical reaction kinetics thereof. LSC@MnO₂ core/shell nanorods demonstrated good electrochemical performance with high capacitance (570 F g⁻¹ at 1 A g⁻¹), and revealed excellent cycling stability (capacitance retention remains at 97.2% after 5000 cycles). The asymmetric supercapacitor device (LSC@MnO₂//AC) displayed a desirable energy density of 37.6 W h kg⁻¹ at 375 W kg⁻¹, and still remains at 23.3 W h kg⁻¹ at a high power density of 7489.3 W kg⁻¹, indicating that the LSC@MnO₂ nanorods are an outstanding pseudo-capacitive electrode material, with significant potential for application in high-performance supercapacitors.