Hollow NiO/carbon pompons for efficient lithium ion storage

Abstract

NiO with desirable hollow structures is an attractive anode material for lithium ion batteries (LIBs) owing to their high theoretical capacity and large active surface. However, research on hollow NiO composites is often hindered by their complex synthesis and poorly controlled morphology. Herein, we report the fabrication of a novel hierarchical hollow pompon-like NiO carbon composite utilizing an ionic liquid as a structure directing agent and starting material, which provides a low cost and efficient strategy to obtain hollow NiO composites with a tunable particle morphology. The morphology evolution and phase transition of the hollow structure were monitored by in situ TEM, while the atomic structure of the product was studied by probe aberration corrected STEM. Density functional theory (DFT) simulations reveal that the presence of nitrogen doped carbon can optimize the band structure and density of states of NiO for efficient lithium ion adsorption and diffusion. When applied in LIBs, the hollow pompon-like NiO carbon composite exhibits an intriguing specific capacity of 1014 mA h g⁻¹ after 100 cycles at 0.5C. This study opens up a new way to fabricate novel hollow pompon-like NiO composites for lithium ion storage.