Structural changes and thermal stability of charged LiNi1/3Co1/3Mn1/3O2 cathode material for Li-ion batteries studied by time-resolved XRD

✍ Scribed by Kyung-Wan Nam; Won-Sub Yoon; Xiao-Qing Yang

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 897 KB
• Volume: 189
• Category: Article
• ISSN: 0378-7753
• DOI: 10.1016/j.jpowsour.2008.10.130

✦ Synopsis

Structural changes and their relationship with thermal stability of charged Li 0.33 Ni 1/3 Co 1/3 Mn 1/3 O 2 cathode samples have been studied using time-resolved X-ray diffraction (TR-XRD) in a wide temperature from 25 to 600 • C with and without the presence of electrolyte in comparison with Li 0.27 Ni 0.8 Co 0.15 Al 0.05 O 2 cathodes. Unique phase transition behavior during heating is found for the Li 0.33 Ni 1/3 Co 1/3 Mn 1/3 O 2 cathode samples: when no electrolyte is present, the initial layered structure changes first to a LiM 2 O 4 -type spinel, and then to a M 3 O 4 -type spinel and remains in this structure up to 600 • C. For the Li 0.33 Ni 1/3 Co 1/3 Mn 1/3 O 2 cathode sample with electrolyte, additional phase transition from the M 3 O 4 -type spinel to the MO-type rock salt phase takes place from about 400 to 441 • C together with the formation of metallic phase at about 460 • C. The major difference between this type of phase transitions and that for Li 0.27 Ni 0.8 Co 0.15 Al 0.05 O 2 in the presence of electrolyte is the delayed phase transition from the spinel-type to the rock salt-type phase by stretching the temperature range of spinel phases from about 20 to 140 • C. This unique behavior is considered as the key factor of the better thermal stability of the Li 1-x Ni 1/3 Co 1/3 Mn 1/3 O 2 cathode materials.