Ultra-High Cycling Stability of 3D Flower-like Ce(COOH)₃ for Supercapacitor Electrode via a Facile and Scalable Strategy

An electrode material with high performance, long durability, and low cost for supercapacitors has long been desired in academia and industry. Among all the factors that affect the electrochemical performance and cycling stability of electrode materials, the morphology and intrinsic structure characteristics are the most important. In this study, a novel 3D flower-like Ce(COOH)3 electrode material was designed by taking advantage of the Ce3+ and -COOH groups and fabricated by a one-pot microwave-assisted method. The morphology and structure characteristics of the sample were examined by SEM, EDS, TEM, XRD, FT-IR, XPS, N2 adsorption/desorption techniques, and the electrochemical behaviors were investigated in a three-electrode configuration. The Ce(COOH)3 electrode presents an excellent specific capacitance of 140 F g−1 at 1 A g−1, higher than many other previously reported Ce-based electrodes. In addition, it delivers high rate capability that retains 60% of its initial capacitance when the current density is magnified 20 times. Dramatically, the Ce(COOH)3 electrode exhibits an ultra-high cycling stability with capacitance retention of 107.9% after 60,000 cycles, which is the highest durability among reported Ce–organic compound electrodes to the best of our knowledge. The excellent electrochemical performance is ascribed to its intrinsic crystal structure and unique morphology. This work indicates that the 3D flower-like Ce(COOH)3 has significant potential for supercapacitor applications and the facile and scalable synthesis strategy can be extended to produce other metal–organic composite electrodes.