Journal
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
Volume 128, Issue 26, Pages 8694-8698Publisher
AMER CHEMICAL SOC
DOI: 10.1021/ja062027+
Keywords
-
Categories
Ask authors/readers for more resources
The cathode in rechargeable lithium-ion batteries operates by conventional intercalation; Li+ is extracted from LiCoO2 on charging accompanied by oxidation of Co3+ to Co4+; the process is reversed on discharge. In contrast, Li+ may be extracted from Mn4+-based solids, e. g., Li2MnO3, without oxidation of Mn4+. A mechanism involving simultaneous Li and O removal is often proposed. Here, we demonstrate directly, by in situ differential electrochemical mass spectrometry (DEMS), that O-2 is evolved from such Mn4+-containing compounds, Li[Ni0.2Li0.2Mn0.6]O-2, on charging and using powder neutron diffraction show that O loss from the surface is accompanied by diffusion of transition metal ions from surface to bulk where they occupy vacancies created by Li removal. The composition of the compound moves toward MO2. Understanding such unconventional Li extraction is important because Li-Mn-Ni-O compounds, irrespective of whether they contain Co, can, after O loss, store 200 mAhg(-1) of charge compared with 140 mAhg(-1) for LiCoO2.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available