  New electrode materials for alkaline-ion batteries are a timely topic. Among
many promising candidates, V2O5 is one of the most interesting cathode
materials. While having very high theoretical capacity, in practice, its
performance is hindered by low stability and poor conductivity. As regards
theoretical descriptions of V2O5, common DFT-GGA calculations fail to reproduce
both the electronic and crystal structure. While the band gap is
underestimated, the interlayer spacing is overestimated as weak dispersion
interactions are not properly described within GGA. Here we show that the
combination of the DFT+U method and semi-empirical D2 correction can compensate
for the drawbacks of the GGA approximation when it comes to the modelling of
V2O5. When compared to common PBE calculations, with a modest increase of the
computational cost, PBE+U+D2 fully reproduced the experimental band gap of
V2O5, while the errors in the lattice parameters are only a few percent. Using
the proposed PBE+U+D2 methodology we studied V2O5 doped with 3d elements (from
Sc to Zn). We show that both the structural and electronic parameters are
affected by doping. Most importantly, a significant increase of conductivity is
expected upon doping, which is of great importance for the application of V2O5
in metal-ion batteries.

Materials Science