掺杂氢氧化镍电子结构的量子化学DV-Xα方法研究

Study on the Electronic Structure of Doped Nickel Hydroxide using the DV-Xα Method of Quantum Chemistry

用量子化学DV-Xα方法计算氢氧化镍Ni7O12H122+、Ni6ZnO12H212+、Ni6CuO12H122+、Ni6CaO12H122+原子簇的电子结构.通过对态密度、电荷集居数、净电荷、电荷密度差、电离能和跃迁能的分析表明,在氢氧化镍中加入Zn、Cu能增强Ni原子与氧原子的相互作用,强化Ni—O键,提高了氢氧化镍结构的稳定性,有利于延长其循环寿命;而Ca的添加会减弱镍原子和氧原子间的相互作用.添加Zn、Cu、Ca都能降低氢氧化镍的电离能,提高跃迁能,促进电子在体系中的传递,有利于改善氢氧化镍电极的电化学性能.但是,过量的钙可能引起氢氧化镍的结构改变而使其失去电化学活性.

The electronic structures of Ni7O12H^2＋ 12, Ni6ZnO12H^2＋ 12 Ni6CuO12H^2＋ 12 and Ni6CaO12H^2＋ 12; clusters were calculated using the DV-Xα 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 O 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.