Premium
X‐ray Absorption Spectroscopy Investigation of Lithium‐Rich, Cobalt‐Poor Layered‐Oxide Cathode Material with High Capacity
Author(s) -
Buchholz Daniel,
Li Jie,
Passerini Stefano,
Aquilanti Giuliana,
Wang Diandian,
Giorgetti Marco
Publication year - 2015
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.201402324
Subject(s) - redox , cobalt , manganese , electrochemistry , lithium (medication) , cathode , absorption (acoustics) , materials science , inorganic chemistry , oxide , oxygen , absorption spectroscopy , chemistry , electrode , metallurgy , composite material , medicine , physics , organic chemistry , quantum mechanics , endocrinology
We present an ex situ X‐ray absorption spectroscopy investigation into lithiation–delithiation of the lithium‐rich, but cobalt‐poor cathode material Li[Li 0.2 Ni 0.16 Mn 0.56 Co 0.08 ]O 2 . The main focus of this work is to address the role of manganese and oxygen in the electrochemical redox process and, especially, to identify the phenomena occurring during the initial activation, that is, during the first delithiation–lithiation cycle. Although manganese is not taking part in the initial electrochemical oxidation process, the results indicate that complete Ni 2+ /Ni 4+ and partial Co 3+ /Co 4+ redox processes occur. The electrochemical performance of the material, considering the full and partial redox inactivity of Mn and Co, reveals the participation of oxygen in the overall electrochemical redox process. Finally, it is found, surprisingly, that a partial reduction of Co and Ni takes place at the end of the initial activation.