关键词: 锂离子电池, 富锂正极材料, 电子性质, 晶格氧, 密度泛函理论

Abstract: This study employs density functional theory (DFT) first-principles calculations to elucidate the stabilization mechanism of lithium-rich manganese-based materials through Mo substitution for Mn. Mo doping mitigates the volume change rate, decreasing it from -2.95% to -0.53% and improving lattice distortion both before and after lithiation. Results from vacancy formation energy and Bader charge analysis reveal a marked increase in the formation energy of seven oxygen vacancies, with the average Bader charge of the first-coordination oxygen escalating from 1.13 to 1.18, effectively suppressing unstable oxygen precipitation. The change in Bader charge of oxygen atoms before and after lithiation decreases from 0.51 to 0.11, indicative of the robust stability of the oxygen framework during cycling. Differential charge density calculations illustrate that Mo can compensate for charge after the removal of Li. Furthermore, Mo doping enhances lithium ion migration rates, reducing the minimum barrier from 0.55 eV to 0.42 eV. This study provides a rigorous theoretical foundation for the doping of high-valence elements in lithium-ion battery cathode materials.

Key words: Lithium-ion battery, Lithium-rich cathode materials, Electronic property, Lattice oxygen, Density functional theory