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Molybdenum Substitution for Improving the Charge Compensation and Activity of Li 2 MnO 3
Author(s) -
Ma Jun,
Zhou YongNing,
Gao Yurui,
Kong Qingyu,
Wang Zhaoxiang,
Yang XiaoQing,
Chen Liquan
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201402727
Subject(s) - molybdenum , cathode , electrochemistry , materials science , lithium (medication) , ion , crystal structure , inorganic chemistry , chemistry , electrode , crystallography , metallurgy , medicine , organic chemistry , endocrinology
Lithium‐rich layer‐structured oxides x Li 2 MnO 3 ⋅ (1− x )LiMO 2 (0< x <1, M=Mn, Ni, Co, etc.) are interesting and potential cathode materials for high energy‐density lithium ion batteries. However, the characteristic charge compensation contributed by O 2− in Li 2 MnO 3 leads to the evolution of oxygen during the initial Li + ion extraction at high voltage and voltage fading in subsequent cycling, resulting in a safety hazard and poor cycling performance of the battery. Molybdenum substitution was performed in this work to provide another electron donor and to enhance the electrochemical activity of Li 2 MnO 3 ‐based cathode materials. X‐ray diffraction and adsorption studies indicated that Mo 5+ substitution expands the unit cell in the crystal lattice and weakens the LiO and MnO bonds, as well as enhancing the activity of Li 2 MnO 3 by lowering its delithiation potential and suppressing the release of oxygen. In addition, the chemical environment of O 2− ions in molybdenum‐substituted Li 2 MnO 3 is more reversible than in the unsubstituted sample during cycling. Therefore molybdenum substitution is expected to improve the performances of the Li 2 MnO 3 ‐based lithium‐rich cathode materials.