# Dresden 2020 – wissenschaftliches Programm

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# CPP: Fachverband Chemische Physik und Polymerphysik

## CPP 89: Materials for Energy Storage (joint session KFM/CPP)

### CPP 89.1: Vortrag

### Donnerstag, 19. März 2020, 09:30–09:50, HSZ 301

Investigation of Li diffusion mechanisms in V_{2}O_{5} — •Fabian Dietrich and Eduardo Cisternas Jara — Núcleo Milenio MultiMat & Departamento de Ciencias Físicas, Universidad de La Frontera, Temuco, Chile

Vanadium pentoxide (V_{2}O_{5}) is a promising candidate for the use as cathode material in lithium ion batteries (LiB) due to its layered structure. For the use as electrode material, it is necessary to understand fundamental aspects of its structure as well as mechanisms during the charging and discharging process. Hence, we investigate the diffusion of lithium ions in that material, paying attention to vanadium pentoxide species with different amount of inserted lithium.

The investigations are done by simulation of the processes using density functional theory (DFT) in the periodic boundary condition, also in combination with plane-wave basis sets and dispersion correction. Diffusion pathways are calculated using the nudged-elastic band (NEB) method. Resulting barrier heights are used for subsequent Monte-Carlo simulations. Frequency calculations are used to estimate the diffusion coefficients, which are also used in the MC simulations.

We assumed different diffusion mechanisms for the pure V_{2}O_{5} and the lithiated species LiV_{2}O_{5}. While in V_{2}O_{5} a quite free diffusion of Li ions is possible, the occupation of distinct lattice positions by Li ions leads to a blocking of certain pathways. Thus, the knock-off mechanism is proposed for LiV_{2}O_{5}. This assumption could be confirmed by the calculations, comparing different mechanisms for the diffusion in LiV_{2}O_{5}.