SAIP2026

Dopant-Concentration Dependence of Structural and Transport Properties in Ni/Co-Doped LiMn2O4 spinel from Molecular Dynamics Simulations

8 Jul 2026, 16:20

1h 20m

Great Hall ( University of the Western Cape)

Poster Presentation Track A - Physics of Condensed Matter and Materials Poster Session 2

Speaker

Mr Tharollo Malepe (University of Limpopo)

Description

Molecular dynamics simulations were employed to investigate the effect of Li+ transport in Co- and Ni-doped spinel nanostructures. LiMn2-xMxO4 (0 ≤ x ≤ 0.08, M=Co and Ni) spinel nanostructures were successfully generated with the simulated amorphization and recrystallization. The spinel structure, which is a promising cathode material for lithium-ion batteries due to its cost-effectiveness, high-rate capabilities, and environmental benignity. The study revealed that the MO6 (M=Mn, Co, Ni) framework can be improved by partially substituting Mn with Co or Ni, which is in good accord with previous studies. It was also found that the structural stabilization with Co and Ni can also positively influence the transport of Li+ ions in the spinel structure. The Li+ diffusion coefficients of Li+ ions in LiMn1.92Co0.08O4 and LiMn1.92Ni0.08O4 were found to be 5.538 x 10-6 cm2/s, 6.359 x 10-6 cm2/s, and 2.971 x 10-5 cm2/s at 300 K, respectively. Correspondingly, at the temperature of 340 K, the diffusion coefficient of Li+ ions in LiMn1.92Co0.08O4 and LiMn1.92Ni0.08O4 is 8.142 x 10-6 cm2/s, 8.502 x 10-6 cm2/s, and 4.213 x 10-5 cm2/s, respectively. The Ni-doped spinel nanostructure exhibits remarkable Li+ ion transport, which is crucial for large-scale applications, particularly in electric vehicles. It is also very crucial to optimize the Co or Ni content to achieve peak performance. The current study uncovered that increasing the concentration of Ni could be detrimental to the transport of Li+ ions in the spinel structure. However, increasing the Ni content was found to improve the diffusion of Li+ ions in the material, despite previous findings suggesting otherwise. Moreover, the study also demonstrated that Nano-structuring can substantially improve the diffusion of Li+ ions in the spinel structure. The structural stability, rate capability, and practical capacity of LiMn2O4 spinel cathode material can be enhanced through partial substitution of Mn with Ni and Co.