A Stable Nanostructured Li-Deficient Oxide Thin-Film Electrode for Advanced Lithium-Ion Batteries

Recently, lithium-ion batteries have been used heavily in consumer electronics worldwide, and their use is expanding to electric vehicles and other high power transportation applications as their prices continue to decline. However, one of the main issues for the transportation application is the need to develop high-performance cathode materials. Here we report a novel nanostructured cathode material based on air-stable Li-deficient oxide thin film (Li_0.28Co_0.29Ni_0.30Mn_0.20O₂) for high-energy density lithium-ion batteries. This film is prepared via a method combining radio frequency magnetron sputtering and in-situ post-annealing using a crystalline and stoichiometric LiCo_1/3Ni_1/3Mn_1/3O₂ target. This Li-deficient oxide thin film has a polycrystalline nanostructure, high tap density, and higher energy and power densities compared to the initial stoichiometric LiCo_1/3Ni_1/3Mn_1/3O₂. It surprisingly delivers large reversible capacity (216 mA h g⁻¹), good cycle performance and superior rate capability. Such a material is a promising cathode candidate for high-energy lithium-ion batteries, especially thin-film batteries.