Uniform second Li ion intercalation in solid state ϵ-LiVOPO4

Full, reversible intercalation of two Li+ has not yet been achieved in promising VOPO4 electrodes. A pronounced Li+ gradient has been reported in the low voltage window (i.e., second lithium reaction) that is thought to originate from disrupted kinetics in the high voltage regime (i.e., first lithiu...

Full description

Saved in:
Bibliographic Details
Published in:Applied physics letters 2016-08, Vol.109 (5)
Main Authors: Wangoh, Linda W., Sallis, Shawn, Wiaderek, Kamila M., Lin, Yuh-Chieh, Wen, Bohua, Quackenbush, Nicholas F., Chernova, Natasha A., Guo, Jinghua, Ma, Lu, Wu, Tianpin, Lee, Tien-Lin, Schlueter, Christoph, Ong, Shyue Ping, Chapman, Karena W., Whittingham, M. Stanley, Piper, Louis F. J.
Format: Article
Language:English
Subjects:
charge transport
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
defects
ENERGY STORAGE
energy storage (including batteries and capacitors)
ENGINEERING
materials and chemistry by design
MATERIALS SCIENCE
synthesis (novel materials)
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Full, reversible intercalation of two Li+ has not yet been achieved in promising VOPO4 electrodes. A pronounced Li+ gradient has been reported in the low voltage window (i.e., second lithium reaction) that is thought to originate from disrupted kinetics in the high voltage regime (i.e., first lithium reaction). Here, we employ a combination of hard and soft x–ray photoelectron and absorption spectroscopy techniques to depth profile solid state synthesized LiVOPO4 cycled within the low voltage window only. Analysis of the vanadium environment revealed no evidence of a Li+ gradient, which combined with almost full theoretical capacity confirms that disrupted kinetics in the high voltage window are responsible for hindering full two lithium insertion. Furthermore, we argue that the uniform Li+ intercalation is a prerequisite for the formation of intermediate phases Li1.50VOPO4 and Li1.75VOPO4. The evolution from LiVOPO4 to Li2VOPO4 via the intermediate phases is confirmed by direct comparison between O K–edge absorption spectroscopy and density functional theory.
ISSN:0003-6951