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

A two-step method was successfully used to synthesize CSD-LaNiO3/NiO with a large specific surface area. The specific capacitance of CSD-LaNiO3/NiO was estimated to 326.8 F g(- 1), a value better than those of LaNiO3 (166.5 F g(-1)) and NiO (44.2 F g(- 1)). The reason for this was attributed to the highly conductive LaNiO3 core, providing high-speed electronic channels. The NiO shell of the capacitor showed superior theoretical specific capacities due to the synergy effect.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 super-capacitor electrodes. In this work, a two-step method with low cost and convenient operation was devel-oped 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. (C) 2022 Elsevier Inc. All rights reserved.