美国卡内基梅隆大学Venkatasubramanian Viswanathan团队报道了富锂电池材料中氧轨道的层析重构方法。相关研究成果于2021年6月9日发表于国际顶尖学术期刊《自然》。
重型运输和航空的电气化需要新的策略来提高电极材料的能量密度。使用阴离子氧化还原是实现这一宏伟目标的一种可能途径。然而，由于氧化还原反应相关的电子轨道不能通过标准实验测量，关于O2/O氧化还原范例的有效性以及阴离子容量起源的替代解释仍然存在问题。
该文中，利用高能X射线康普顿测量和第一性原理模型，研究人员展示了如何对处于可逆和稳定阴离子氧化还原活性中心的电子轨道进行成像和可视化，并确定其特征和对称性。研究人员发现康普顿分布随锂离子浓度的差异变化对电子波函数的相位敏感，并带有静电和共价键效应的特征。该研究不仅在原子尺度上提供了富锂电池的工作原理，而且还提出了改进现有电池材料和设计新电池材料的途径。
附：英文原文
Title: Tomographic reconstruction of oxygen orbitals in lithium-rich battery materials
Author: Hasnain Hafiz, Kosuke Suzuki, Bernardo Barbiellini, Naruki Tsuji, Naoaki Yabuuchi, Kentaro Yamamoto, Yuki Orikasa, Yoshiharu Uchimoto, Yoshiharu Sakurai, Hiroshi Sakurai, Arun Bansil, Venkatasubramanian Viswanathan
Issue&Volume: 2021-06-09
Abstract: The electrification of heavy-duty transport and aviation will require new strategies to increase the energy density of electrode materials1,2. The use of anionic redox represents one possible approach to meeting this ambitious target. However, questions remain regarding the validity of the O2/O oxygen redox paradigm, and alternative explanations for the origin of the anionic capacity have been proposed3, because the electronic orbitals associated with redox reactions cannot be measured by standard experiments. Here, using high-energy X-ray Compton measurements together with first-principles modelling, we show how the electronic orbital that lies at the heart of the reversible and stable anionic redox activity can be imaged and visualized, and its character and symmetry determined. We find that differential changes in the Compton profile with lithium-ion concentration are sensitive to the phase of the electronic wave function, and carry signatures of electrostatic and covalent bonding effects4. Our study not only provides a picture of the workings of a lithium-rich battery at the atomic scale, but also suggests pathways to improving existing battery materials and designing new ones.
DOI: 10.1038/s41586-021-03509-z
Source: https://www.nature.com/articles/s41586-021-03509-z