Study on the electronic structure of doped nickel hydroxide using the DV-Xα method of quantum chemistry

The electronic structures of Ni7O12H122+, Ni6ZnO12H122+, Ni6CuO12H122+, and Ni6CaO12H122+ clusters were calculated using the DV-X alpha method of quantum chemistry. By analyzing the density of states, the orbital populations, the net charges, the ionization energies, the transition energies, and the electric charge density differences of the selected clusters, it was indicated that the interaction between Ni and 0 was enhanced by adding Zn and Cu to nickel hydroxide, and the Ni-O bond was strengthened. As a result, the structural stability of nickel hydroxide was improved and the cycling life of the electrode was extended. However, the addition of Ca weakened the interaction. The ionization energy was dropped and transition energy was elevated by the doping of Zn, Cu, and Ca, and thus the transfer of electrons in electrode materials was accelerated and the electrochemical performance of nickel hydroxide electrode was improved. However, excessive Ca-dopped will change the structure of nickel hydroxide and will deteriorate its electrochemical performance.