First-principles simulations were performed using spin polarized density-functional theory (DFT) as implemented in the Vienna Ab-initio Simulation Package (VASP). To describe the exchange-correlation energy, the generalized-gradient approximation (GGA) developed by Perdew, Burke, and Ernzerhof (PBE) was used, and to account for electron correlations, the Hubbard U method was applied. Similar to previous studies of other phases of the Ni-V-O system such as NiV