Two-step fabrication of lanthanum nickelate and nickel oxide core-shell dandelion-like materials for high-performance supercapacitors

LaNiO3 and NiO are promising materials for supercapacitor applications. However, it is still challenging to design special structures based on these materials to improve the electrochemical performances of supercapacitor electrodes. In this work, a two-step method with low cost and convenient operation was developed to prepare dandelion-shaped LaNiO3/NiO (CSD-LaNiO3/NiO) with core-shell structure. The as-obtained CSD-LaNiO3/NiO showed high conductivity due to the core LaNiO3, which helped to provide an efficient electron transmission path for the shell NiO, producing a strong synergistic effect. The results of electrochemical properties of CSD-LaNiO3/NiO, LaNiO3 and NiO samples revealed the superior specific capacitance of CSD-LaNiO3/NiO (326.8 F g-1) at 1 A g-1 compared to LaNiO3 (166.5 F g-1) and NiO (44.2 F g-1). The as-obtained CSD-LaNiO3/NiO material was then mixed with activated carbon and assembled into an asymmetric supercapacitor, which exhibited a wide potential window of 1.8 V, energy density of 30.4 Wh kg-1 at 1800 W kg-1, and specific capacity retention of 97.7% after 3000 cycles. In sum, the as-obtained core-shell nanostructure prepared by the proposed synthesis method is very promising for future development of high-performance supercapacitors.