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Title: Characterization of Cathode Materials for Rechargeable Lithium Batteries using Synchrotron Based In Situ X-ray Techniques

Abstract

The emergence of portable telecommunication, computer equipment and ultimately hybrid electric vehicles has created a substantial interest in manufacturing rechargeable batteries that are less expensive, non-toxic, operate for longer time, small in size and weigh less. Li-ion batteries are taking an increasing share of the rechargeable battery market. The present commercial battery is based on a layered LiCoO{sub 2} cathode and a graphitized carbon anode. LiCoO{sub 2} is expensive but it has the advantage being easily manufactured in a reproducible manner. Other low cost layered compounds such as LiNiO{sub 2}, LiNi{sub 0.85}Co{sub 0.15}O{sub 2} or cubic spinels such as LiMn{sub 2}O{sub 4} have been considered. However, these suffer from cycle life and thermal stability problems. Recently, some battery companies have demonstrated a new concept of mixing two different types of insertion compounds to make a composite cathode, aimed at reducing cost and improving self-discharge. Reports clearly showed that this blending technique can prevent the decline in ·capacity caused by cycling or storage at elevated temperatures. However, not much work has been reported on the charge-discharge characteristics and phase transitions for these composite cathodes. Understanding the structure and structural changes of electrode materials during the electrochemical cycling is the key tomore » develop better .lithium ion batteries. The successful commercialization of the· lithium-ion battery is mainly built on the advances in solid state chemistry of the intercalation compounds. Most of the progress in understanding the lithium ion battery materials has been obtained from x-ray diffraction studies. Up to now, most XRD studies on lithium-ion battery materials have been done ex situ. Although these ex situ XRD studies have provided important information· about the structures of battery materials, they do face three major problems. First of all, the pre-selected charge (discharge) states may not be representative for the full picture of the structural changes during charge (discharge). In other words, the important information might be missed for those charge (discharge) states which were not selected for ex situ XRD studies. Secondly, the structure of the sample may have changed after removed from the cell. Finally, it is impossible to use the ex situ XRD to study the dynamic effects during high rate charge-discharge, which is crucial for the application of lithium-ion batteries for electric vehicle. A few in situ studies have been done using conventional x-ray tube sources. All of the in situ XRD studies using conventional x-ray tube sources have been done in the reflection mode in cells with beryllium windows. Because of the weak signals, data collection takes a long time, often several hundred hours for a single charge-discharge cycle. This long time data collection is not suitable for dynamic studies at all. Furthermore, in the reflection mode, the x-ray beam probes mainly the surface layer of the cathode materials. Iri collaboration with LG Chemical Ltd., BNL group designed and constructed the cells for in situ studies. LG Chemical provided several blended samples and pouch cells to BNL for preliminary in situ study. The LG Chemical provided help on integrate the blended cathode into these cells. The BNL team carried out in situ XAS and XRD studies on the samples and pouch cells provided by LG Chemical under normal charge-discharge conditions at elevated temperature.« less

Authors:
ORCiD logo;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
973810
Report Number(s):
BNL-91107-2010-CRAD
C-06-02
DOE Contract Number:  
SC0012704
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION

Citation Formats

Yang, Xiao-Qing, and Furey, Michael. Characterization of Cathode Materials for Rechargeable Lithium Batteries using Synchrotron Based In Situ X-ray Techniques. United States: N. p., 2007. Web. doi:10.2172/973810.
Yang, Xiao-Qing, & Furey, Michael. Characterization of Cathode Materials for Rechargeable Lithium Batteries using Synchrotron Based In Situ X-ray Techniques. United States. doi:10.2172/973810.
Yang, Xiao-Qing, and Furey, Michael. Wed . "Characterization of Cathode Materials for Rechargeable Lithium Batteries using Synchrotron Based In Situ X-ray Techniques". United States. doi:10.2172/973810. https://www.osti.gov/servlets/purl/973810.
@article{osti_973810,
title = {Characterization of Cathode Materials for Rechargeable Lithium Batteries using Synchrotron Based In Situ X-ray Techniques},
author = {Yang, Xiao-Qing and Furey, Michael},
abstractNote = {The emergence of portable telecommunication, computer equipment and ultimately hybrid electric vehicles has created a substantial interest in manufacturing rechargeable batteries that are less expensive, non-toxic, operate for longer time, small in size and weigh less. Li-ion batteries are taking an increasing share of the rechargeable battery market. The present commercial battery is based on a layered LiCoO{sub 2} cathode and a graphitized carbon anode. LiCoO{sub 2} is expensive but it has the advantage being easily manufactured in a reproducible manner. Other low cost layered compounds such as LiNiO{sub 2}, LiNi{sub 0.85}Co{sub 0.15}O{sub 2} or cubic spinels such as LiMn{sub 2}O{sub 4} have been considered. However, these suffer from cycle life and thermal stability problems. Recently, some battery companies have demonstrated a new concept of mixing two different types of insertion compounds to make a composite cathode, aimed at reducing cost and improving self-discharge. Reports clearly showed that this blending technique can prevent the decline in ·capacity caused by cycling or storage at elevated temperatures. However, not much work has been reported on the charge-discharge characteristics and phase transitions for these composite cathodes. Understanding the structure and structural changes of electrode materials during the electrochemical cycling is the key to develop better .lithium ion batteries. The successful commercialization of the· lithium-ion battery is mainly built on the advances in solid state chemistry of the intercalation compounds. Most of the progress in understanding the lithium ion battery materials has been obtained from x-ray diffraction studies. Up to now, most XRD studies on lithium-ion battery materials have been done ex situ. Although these ex situ XRD studies have provided important information· about the structures of battery materials, they do face three major problems. First of all, the pre-selected charge (discharge) states may not be representative for the full picture of the structural changes during charge (discharge). In other words, the important information might be missed for those charge (discharge) states which were not selected for ex situ XRD studies. Secondly, the structure of the sample may have changed after removed from the cell. Finally, it is impossible to use the ex situ XRD to study the dynamic effects during high rate charge-discharge, which is crucial for the application of lithium-ion batteries for electric vehicle. A few in situ studies have been done using conventional x-ray tube sources. All of the in situ XRD studies using conventional x-ray tube sources have been done in the reflection mode in cells with beryllium windows. Because of the weak signals, data collection takes a long time, often several hundred hours for a single charge-discharge cycle. This long time data collection is not suitable for dynamic studies at all. Furthermore, in the reflection mode, the x-ray beam probes mainly the surface layer of the cathode materials. Iri collaboration with LG Chemical Ltd., BNL group designed and constructed the cells for in situ studies. LG Chemical provided several blended samples and pouch cells to BNL for preliminary in situ study. The LG Chemical provided help on integrate the blended cathode into these cells. The BNL team carried out in situ XAS and XRD studies on the samples and pouch cells provided by LG Chemical under normal charge-discharge conditions at elevated temperature.},
doi = {10.2172/973810},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed May 23 00:00:00 EDT 2007},
month = {Wed May 23 00:00:00 EDT 2007}
}

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