Synergistic O2-/Li+ Dual Ion Transportation at Atomic Scale
F. Q. Meng,
Q. H. Zhang,
A. Gao,
X. Z. Liu,
J. N. Zhang,
S. Y. Peng,
X. Lu,
L. Gu,
H. Li
Affiliations
F. Q. Meng
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
Q. H. Zhang
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
A. Gao
School of Materials, Sun Yat-Sen University, Guangzhou 510275, China
X. Z. Liu
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
J. N. Zhang
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
S. Y. Peng
College of Materials Science and Engineering, Jiangxi University of Science and Technology, Jiangxi 341000, China
X. Lu
School of Materials, Sun Yat-Sen University, Guangzhou 510275, China
L. Gu
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
H. Li
Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China; Songshan Lake Materials Laboratory, Dongguan, Guangdong 523808, China; School of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049, China
The ion migration during electrochemical process is a fundamental scientific issue for phase transition behavior and of technical importance for various functional devices, where cations or anions are active under electrical bias. Usually only one type of functional ion, O2- or Li+, is activated due to their different migration energy barriers, cooperated by the valence change of other immobile ions in the host lattice matrix, e.g., Co2+/Co3+ and Mn3+/Mn4+ redox couples, owing to the charge neutralization. Here we select spinel Li4Ti5O12 as anode and construct an all-solid-state battery under a transmission electron microscope; a synergistic transportation of O2- and Li+ driven by an electrical bias was directly observed at the atomic scale. A small amount of oxygen anions was extracted firstly as a result of its lowest vacancy formation energy under 2.2 V, leading to the vertical displacement of oxygen. Up to 2.7 V, an ordered phase with both Li- and O- deficiency formed. The Li+ and O2- ions are simultaneously extracted out from the [LiO4] tetrahedra due to the electroneutrality principle. The migration paths of O and Li have been proposed and verified by first-principles calculations. These results reveal a brand new synergistic ion migration manner and may provide up-to-date insights on the transportation process of lithium ion conductors.
