Abstract:
There is a growing interest in finding a suitable electrolyte material for the construction of
rechargeable Li-ion batteries. Li2NiGe3O8
is a material of interest with modest Li-ionic conductivity.
The atomistic simulation technique was applied to understand the defect processes and Li-ion
diffusion pathways, together with the activation energies and promising dopants on the Li, Ni, and Ge
sites. The Li-Ni anti-site defect cluster was found to be the dominant defect in this material, showing
the presence of cation mixing, which can influence the properties of this material. Li-ion diffusion
pathways were constructed, and it was found that the activation energy for a three-dimensional
Li-ion migration pathway is 0.57 eV, which is in good agreement with the values reported in the
experiment. The low activation energy indicated that Li-ion conductivity in Li2NiGe3O8
is fast. The
isovalent doping of Na, Fe and Si on the Li, Ni and Ge sites is energetically favorable. Both Al and Ga
are candidate dopants for the formation of Li-interstitials and oxygen vacancies on the Ge site. While
Li-interstitials can improve the capacity of batteries, oxygen vacancies can promote Li-ion diffusion.
