Study of the Jahn–Teller Distortion in LiNiO2, a Cathode Material in a Rechargeable Lithium Battery, byin SituX-Ray Absorption Fine Structure Analysis

✍ Scribed by Izumi Nakai; Kouta Takahashi; Youhei Shiraishi; Tatsuji Nakagome; Fumishige Nishikawa

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 255 KB
• Volume: 140
• Category: Article
• ISSN: 0022-4596
• DOI: 10.1006/jssc.1998.7943

✦ Synopsis

Structural changes accompanying the electrochemical Li deintercalation of Li 1؊x NiO 2 and Li 1؊x CoO 2 were studied by the transmission X-ray absorption fine structure (XAFS) technique using an in situ X-ray cell of original design. Our results revealed that the Jahn-Teller distortion of the Ni-O octahedra found in LiNiO 2 decreased as the Li ion was removed from the cathode. The observed X-ray absorption near-edge structures (XANES) of Li 1؊x NiO 2 and Li 1؊x CoO 2 as a function of x are consistent with the phase transitions found by powder-diffraction studies. The Ni-O, Co-O, and Ni-Ni interatomic distances decreased almost linearly as the Li content decreased to x ‫؍‬ 0.8, while the Co-Co distance slightly decreased to x ‫؍‬ 0.5 and increased up to x ‫؍‬ 0.8. The local distortion of NiO 6 octahedra also decrease with increasing y in a Li(Ni 1؊y , Co y )O 2 solid solution.