Engineering the surface of rutile TiO₂ nanoparticles with quantum pits towards excellent lithium storage

Engineering the surface structure of nanomaterials is of great importance for applications in energy conversion and storage. Herein, unique rutile TiO₂ nanoparticles have been successfully synthesized by a facile solution and subsequent thermal annealing method. Each particle surface has been etched to form pits with an average size of 2-5 nm, producing abundant steps and vacancies. When evaluated as anode materials for lithium-ion batteries, the yielded rutile TiO₂ nanoparticle electrode exhibits a maximum specific capacity of ∼145 mA h g^-1 at a current density of 0.5C (1C = 335 A g^-1) with outstanding charge/discharge rate capability (∼102 mA h g^-1 at 5C) and good cycling performance.