Study on Li ion diffusion in Li_xV₂O₅ using first principle calculations and kinetic Monte Carlo simulations

Abstract

We study the Li diffusion in LixV2O5 (0 < x < 1) - a potential cathode material for Lithium ion batteries. Different diffusion pathways in this material in dependence on the Li ion concentration are investigated by applying first-principles calculations. The results are used to obtain the corresponding diffusion coefficients by employing two complementary methodologies: Kinetic Monte Carlo (KMC) simulations and a statistical thermodynamics approach. The KMC simulations for two different crystal planes give new evidence that the diffusion occurs mainly along the [010] direction, while the corresponding diffusion coefficients show a temperature dependence obeying the Arrhenius' Law. The necessity of the consideration of concentration-dependent barrier heights in the KMC simulations are demonstrated by looking at the significant changes of the concentration-dependence of the diffusion cofficients. The simulated diffusion coefficients of the combined approach show a good quantitative agreement with experimental data reported previously.

V2O5@ZIF-8 with a Stable Structure and a Fast Ion Diffusion Channel as a Promising Cathode Material for Lithium-Ion Batteries

“…due to the layered structure of V 2 O 5 held together by van der Waals forces. − It can serve as a good host for reversible Li + insertion/extraction; multiple electrons could be captured by V 2 O 5 , and the process could be expressed according to the equation V 2 O 5 + x Li + + x e – ⇔ Li x V 2 O 5. , Unfortunately, the bulk V 2 O 5 in LIBs suffers from poor ion diffusivity (10 –12 cm 2 s –1 ) and low electronic conductivity (10 –4 to 10 –7 S cm –1 ) now, which leads to low discharge capacity density at high discharge current and poor structural stability during long periods of charge and discharge. − …”