Precisely synthesized LiF-tipped CoF₂-nanorod heterostructures improve energy storage capacities

CoF₂, with a relatively high theoretical capacity (553 mA h g^-1), has been attracting increasing attention in the energy storage field. However, a facile and controllable synthesis of monodispersed CoF₂ and CoF₂-based nano-heterostructures have been rarely reported. In this direction, an eco-friendly and precisely controlled colloidal synthesis strategy to grow uniformly sized CoF₂ nanorods and LiF-tipped CoF₂-nanorod heterostructures based on a seeded-growth method is established. The unveiled selective growth of LiF nanoparticles onto the two end tips of the CoF₂ nanorods is associated with the higher energy of tips, which favors the nucleation of LiF nanocrystals. Notably, it was found that LiF could protect CoF₂ from corrosion even after 9 months of aging. In addition, the as-obtained heterostructures were employed in supercapacitors and lithium sulfur batteries as cathode materials. The heterostructures consistently exhibited higher specific capacities than the corresponding two single components in both types of energy storage devices, making it a potential electrode material for energy storage applications.