Stoichiometric (Li₂O₂)_n clusters (n = 1–6) were systematically studied by density functional theory calculations with hybrid B3LYP functional. The most stable structures of these clusters are triplet except for the Li₂O₂ monomer. In the Li₂O₂ monomer, the closed shell singlet is strongly favored. There are superoxide-like characteristics in terms of bond lengths and spin in the stoichiometric peroxide lithium clusters, which may have implications for the formation and decomposition of peroxide lithium in Li–O₂ batteries. Furthermore, the growth process of the lowest energy structures of (Li₂O₂)_n clusters is “ring-like” (n = 2) → “rectangle-like” (n = 3,4) → “Y-like” (n = 5) → “disc-like” (n = 6) feature, this growth pattern is in good agreement with the experimental observation at the initial phase of discharge in the Li–O₂ battery. In addition, the values of energy gaps for the (Li₂O₂)_n clusters are much smaller than the band gap of bulk phase, and thus the (Li₂O₂)_n cluster can enhance the electron conductivity in the peroxide lithium. The frontier molecular orbitals analysis indicates that there are π^* antibonding on the surface of (Li₂O₂)_n clusters, making their structures more stable. Finally, the PES of (Li₂O₂)_n clusters have been simulated, we hope that our simulated PES can be compared with future experimental data.

中文翻译：

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化学计量小的（Li 2 O 2）n团簇的结构和电子性质及其与Li–O 2电池的相关性

 利用混合B3LYP泛函通过密度泛函理论计算系统地研究了化学计量（Li ₂ O ₂）_n团簇（n = 1-6）。除Li ₂ O ₂单体外，这些簇的最稳定结构是三重态。在Li ₂ O ₂单体中，强烈优选闭壳单线态。在化学计量的过氧化物锂簇中，在键长和自旋方面具有超氧化物样特征，这可能对Li-O ₂电池中过氧化物锂的形成和分解有影响。此外，（Li ₂O ₂）_n个簇是“环状”（n  = 2）→“矩形”（n  = 3,4）→“ Y状”（n  = 5）→“盘状”（n  = 6 ）特性，这种生长方式与Li-O ₂电池放电初期的实验观察结果非常吻合。此外，（Li ₂ O ₂）_n团簇的能隙值远小于体相的带隙，因此（Li ₂ O ₂）_n团簇可以增强过氧化锂中的电子电导率。前沿分子轨道分析表明，（Li ₂ O ₂）_n团簇表面存在π ^*反键，使其结构更稳定。最后，对（Li ₂ O ₂）_n团簇的PES进行了模拟，我们希望我们的模拟PES可以与未来的实验数据进行比较。