Center for Study of Science, Technology and Policy (CSTEP), Bangalore 560094, India.
Phys Chem Chem Phys. 2018 Jul 25;20(29):19606-19613. doi: 10.1039/c8cp03148g.
Oxygen removal from high capacity Li-rich layered oxide Li1.17Ni0.17Mn0.5Co0.17O2 affects the charge transfer process during cycling. During de-lithiation, oxygen removal takes place with the reduction in oxygen binding energy. Co substitution affects oxygen removal by shifting the O-p orbital closer to the Fermi energy. A convex hull plot is used to analyse single-phase and two-phase reactions during de-lithiation in Li1.17Ni0.17Mn0.5Co0.17O2 and Li2MnO3. Experimentally, the single-phase and two-phase reactions are identified based on the characteristics of the charge curve. In the charge transfer process more than 80% of lithium charge is transferred to oxygen in both the compounds. Effective charge and cyclic voltammetry reveal the redox centers in the compounds which help to understand the role of oxygen and transition metals in de-lithiation. A detailed explanation of oxygen removal and the charge transfer mechanism of Li1.17Ni0.17Mn0.5Co0.17O2 and Li2MnO3 is provided in the current experimental and density functional theory based study.
从高容量富锂层状氧化物 Li1.17Ni0.17Mn0.5Co0.17O2 中去除氧会影响循环过程中的电荷转移过程。在去锂过程中，随着氧结合能的降低，氧的去除会发生。钴取代通过将 O-p 轨道更接近费米能来影响氧的去除。凸包图用于分析 Li1.17Ni0.17Mn0.5Co0.17O2 和 Li2MnO3 去锂过程中的单相和两相反应。实验上，基于电荷曲线的特征，确定单相和两相反应。在电荷转移过程中，两种化合物中超过 80%的锂电荷转移到氧上。有效电荷和循环伏安法揭示了化合物中的氧化还原中心，有助于理解氧和过渡金属在去锂过程中的作用。目前的实验和基于密度泛函理论的研究提供了对 Li1.17Ni0.17Mn0.5Co0.17O2 和 Li2MnO3 中氧去除和电荷转移机制的详细解释。
