Double perovskite La2CoMnO6 hollow spheres prepared by template impregnation for high-performance supercapacitors

Double perovskite oxides are useful electrode materials in supercapacitors. However, adopting their special structures to improve the electrochemical performances of supercapacitor electrodes is still challenging. In this study, hollow spherical porous La2CoMnO6 (HS-LCMO) materials were prepared using carbon spheres as template impregnation followed by annealing in air to remove the template. The proposed method was advantageous in terms of low-cost, simple operation, large scalability, and improved electrochemical performance of La2CoMnO6. The as-obtained HS-LCMO specimens were tested electrochemically, and the results were compared to reference sample (SG-LCMO) prepared by the sol-gel method. At current density of 1 A g(-1), HS-LCMO showed high specific capacitance of 376 F g(-1), much higher than that of SG-LCMO (94 F g(-1)). To expand the application prospects of supercapacitors, HS-LCMO and activated carbon (AC) were then assembled into asymmetric supercapacitors, and their testing exhibited wide potential window of 2 V with high energy density reaching 65.8 Wh kg(-1) at 1000 W kg(-1). Besides, the supercapacitor devices maintained around 89.2% of the initial capacitance after 3000 cycles. The proposed synthesis strategy looks very promising for preparation of future cathode materials for high-performance supercapacitors.