Synthesis, characterization, and DFT simulation to analyze electrochemical performance of ternary transition metal oxides LiNi_0.80X_0.10Nb_0.10O₂(X=Cu, Zn, Y) for lithium-ion batteries

Nickel (Ni)-rich lithium transition metal oxides(TMO), such as LiNi_0.8 X_0.10Nb_0.10O₂ (where X is Cu, Y, or Zn), characterized by a layered structure, are considered viable cathode options for the development of high energy density lithium-ion batteries, consequently promoting the commercial acceptance of zero-emission electric automobiles. Layered transition metal oxides(TMO) have been suggested as appropriate cathodes for Li-ion batteries due to their favorable voltage window, improving specific capacity and energy density. This study presents a series of ternary layered transition metal oxides, LiNi_0.80Cu_0.10Nb_0.10O₂, LiNi_0.80Y_0.10Nb_0.10O₂, and LiNi_0.80Zn_0.10Nb_0.10O₂, synthesized by the hydrothermal method. XRD patterns exhibit that all the compounds depict a hexagonal structure with an R-3m space group. After heating them at 750 °C for 20h in an air furnace, the patterns are recorded for the prepared samples. The synthesized samples exhibited single-phase diffraction patterns with very sharp peaks. This indicates the high crystallinity of the powder cathode materials. SEM micrographs revealed the development of distinctly separated particles with diverse shapes. The crystal structure was generated using Wien2k software with the lattice constants determined by experimental data of the prepared sample. The calculated spin-polarized electronic band structures and density of states (DOS) for all three compounds indicated metallic behavior. The ferromagnetic characteristics of the substitutional material are validated by the negative values of the exchange constants (N_օα and N_օβ). The thermoelectric properties, including the Seebeck coefficient, thermal conductivity, electrical conductivity, and figure of merit, were calculated using the BoltzTraP code. Theoretical calculations of average intercalation voltages (AIV) were derived from the total energies of the optimized compounds and their di-lithiated phases. An electrochemical analysis showed that the values for theoretical discharge capacity and AIV for ternary layered transition metal oxides LiNi_0.80X_0.10Nb_0.10O₂(X = Cu, Zn, Y) were found to be 1547 mAhg^{− 1},1543 mAhg^{− 1},1489 mAhg^{− 1} and 4.4V, 5.4V, 5.5V, respectively. Experimental and theoretical investigations indicate that the examined ternary layered transition metal oxides are appropriate cathode materials for coin cell fabrication.