Insight into behaviors and properties of AMO2 (A = Na and Li; M = Mn, Fe, Co, Ni, and Ni1/3Co1/3Mn1/3) cathode materials: A DFT evaluation

Abstract

Density functional theory (DFT), utilizing GGA(+U), is used to theoretically investigate and compare two important families of layered oxide cathode materials for lithium and sodium -ion batteries namely, Li/NaCoO2, Li/NaMnO2, Li/NaNiO2, Li/NaFeO2, and Li/NaMn1/3Co1/3Ni1/3O2 (NCM111). Material characterization, including structural characteristics, structural stability, cell voltage, electrochemical, and electrical properties, are taken into account. Comparison between the materials is made by considering the mentioned properties. Especially, electrical properties of the materials are evaluated by four newly established approaches. Calculations offer the highest structure stability for the Li-ion family than Na-ion one. The best and the worst structural stable electrodes are Li/Na(NCM)O2 and Li/NaNiO2, respectively. Li/Na(NCM)O2, LiCoO2, and NaFeO2 cathode materials have the highest voltage among the considered materials. The lowest band gaps belong to Li/Na(NCM)O2, LiNiO2, and NaFeO2. Considering the electrical rate capability, after NaCoO2 electrode, NaMnO2 and LiNiO2 have the lowest rate-capability among the evaluated materials. Generally, NaCoO2 and LiMnO2 are relatively the worst and Li/Na(NCM)O2, LiCoO2, and NaFeO2 are the best among the considered electrode materials. This study offers new insights for investigation of the layered oxide electrode materials for Li-ion and Na-ion batteries.