Electrochemical and microstructural studies of AlPO₄-nanoparticle coated LiCoO₂ for lithium-ion batteries

AlPO₄-nanoparticle coated LiCoO₂ is studied as a positive electrode for lithium rechargeable batteries for a high-voltage charge limit of 4.7V. To understand the role of the coating in transport phenomena and in deintercalation of Li+, the electrochemical behavior is studied alongside the microstructure of the coating. The galvanostatic charge profile is studied with electrochemical impedance tests conducted at various lithium contents during charging. The coating is found to increase the flatness of the two-phase region plateau and to cause the appearance of the monoclinic distortion at x=0.5 as well as distinct plateaus for 03 to H1-3 and H1-3 to 01 transitions, indicating that application of the coating transformed Li-rich LiCoO₂ into stoichiometric LiCoO₂. According to electronic resistance (Re) values from impedance spectra, the coated LiCoO₂ has a more rapid decrease in Re with delithiation, and both materials show a rise in Re above 4.5V. Structurally, SEM images show pitted surface morphology only on the edges of the layers of coated LiCoO₂.

Department dc:contributor.department

Massachusetts Institute of Technology. Dept. of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2006

Author dc:creator

• Appapillai, Anjuli T. (Anjuli Tara)

Advisor dc:contributor.advisor

• Yang Shao-Horn.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/36195

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/36195