Mg~(2+)掺杂锰酸锂的第一性原理研究

利用基于密度泛函理论的第一性原理平面波超软赝势法对Mg~(2+)掺杂锰酸锂的晶格常数与能带结构、态密度、键布居进行计算和分析,计算结果表明:掺杂Mg~(2+)后将会促使Mn、 O原子的电荷重新分布且其相互作用加强,能带带隙减小,费米能级附近的带数增加,费米能由-1.29 eV增加到-1.02 eV, Mn、 O、 Mg在总态密度中贡献比较大,锂离子贡献比较小且峰型尖锐局域化严重,提高了Li~+的扩散效率, Mn—O键变短,共价性增强,形成的共价键较稳定,其相互作用形成的骨架较稳定不易坍塌.从而提高了材料的循环充放电性能和电池使用寿命.

First-principle study on Mg-doped LiMn2O4

By means of the first-principles plane wave supersoft pseudopotential method based on density functional theory, the lattice constant and band structure, density of states and bond population of Mg2+ doped lithium manganate were calculated and analyzed. The calculation results show that after doping Mg2+, the charges of Mn and O atoms will be redistributed and the interaction between them. The band gap will be reduced but the number of bands near the Fermi level will increase, and the Fermi energy will increase from -1.29 eV to -1.02 eV. The O and Mn atoms contributes a lot in the total density of states, the contribution of lithium ions is relatively small and the peak type is sharp and localized, which increases the diffusion efficiency of Li+, the Mn-O bond becomes shorter, the covalence is enhanced, and the covalent formation is formed. The bond is relatively stable, and the skeleton formed by the interaction is relatively stable and is not easy to collapse, thereby improving the cycle charge and discharge performance of the material and the battery life.