Zhu Kefu, Wei Shiqiang, Shou Hongwei, Shen Feiran, Chen Shuangming, Zhang Pengjun, Wang Changda, Cao Yuyang, Guo Xin, Luo Mi, Zhang Hongjun, Ye Bangjiao, Wu Xiaojun, He Lunhua, Song Li
National Synchrotron Radiation Laboratory, CAS Center for Excellence in Nanoscience, University of Science and Technology of China, 230029, Hefei, China.
School of Chemistry and Material Sciences, University of Science and Technology of China, 230026, Hefei, China.
Nat Commun. 2021 Nov 25;12(1):6878. doi: 10.1038/s41467-021-27203-w.
Defect engineering is a strategy that is attracting widespread attention for the possibility of modifying battery active materials in order to improve the cycling stability of the electrodes. However, accurate investigation and quantification of the effect of the defects on the electrochemical energy storage performance of the cell are not trivial tasks. Herein, we report the quantification of vanadium-defective clusters (i.e., up to 5.7%) in the VO lattice via neutron and X-ray powder diffraction measurements, positron annihilation lifetime spectroscopy, and synchrotron-based X-ray analysis. When the vanadium-defective VO is employed as cathode active material in an aqueous Zn coin cell configuration, capacity retention of about 81% after 30,000 cycles at 5 A g is achieved. Density functional theory calculations indicate that the vanadium-defective clusters can provide favorable sites for reversible Zn-ion storage. Moreover, the vanadium-defective clusters allow the storage of Zn ions in VO, which reduces the electrostatic interaction between the host material and the multivalent ions.
缺陷工程是一种因有可能通过修饰电池活性材料来提高电极循环稳定性而备受广泛关注的策略。然而，准确研究和量化缺陷对电池电化学储能性能的影响并非易事。在此，我们通过中子和X射线粉末衍射测量、正电子湮没寿命谱以及基于同步加速器的X射线分析，报告了对VO晶格中钒缺陷团簇（即高达5.7%）的量化。当将钒缺陷的VO用作水系锌硬币电池配置中的阴极活性材料时，在5 A g下经过30,000次循环后可实现约81%的容量保持率。密度泛函理论计算表明，钒缺陷团簇可为可逆锌离子存储提供有利位点。此外，钒缺陷团簇允许锌离子存储在VO中，这降低了主体材料与多价离子之间的静电相互作用。
