Simultaneous Coating and Doping of a Nickel-Rich Cathode by an Oxygen Ion Conductor for Enhanced Stability and Power of Lithium-Ion Batteries

Abstract

With the rapid development of plug-in hybrid electric vehicles and electric vehicles, high-energy layered lithium nickel-rich oxides have received much attention, but there are still many challenges due to the inherent properties of materials. The poor cycling performance and initial capacity loss of the nickel-rich layered oxide are associated with the structural stability of the material and Li⁺/Ni²⁺ cation disorder. Moreover, the synergistic effect of the vacancy of Li and Ni in the delithiation process aggravates the instability of oxygen, eventually resulting in the release of oxygen. It can cause damage to the stability of the structure and even cause safety issues. In this work, we report that Ce_0.8Dy_0.2O_1.9 solid electrolyte inhibits the release of oxygen and improves the structural stability and safety of the Ni-rich cathode material, which is rich in oxygen vacancies. Besides, Ni²⁺ could be oxidized to Ni³⁺ along with the strong oxidation of Ce⁴⁺ doping into the bulk structure, which suppresses the Li⁺/Ni²⁺ cation disorder and improves the initial Coulomb efficiency of the material. This study successfully designed a novel cathode material structure to provide a basis for the future development of layered lithium nickel-rich oxides, which can be used to improve the initial Coulomb efficiency and cycle life.