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Synthesis and Formation Mechanism of a Carbonate Precursor for the Fabrication of LiNi 0.5 Mn 1.5 O 4 Material with a Hierarchical Micro/Nano Architecture
Author(s) -
Qin Xing,
Guo Jianling,
Zhou Mushang,
Zong Bo,
Wang Li,
Liang Guangchuan
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201701196
Subject(s) - ostwald ripening , chemistry , nucleation , carbonate , chemical engineering , crystallization , calcination , hydrothermal circulation , hydrothermal synthesis , electrochemistry , dissolution , inorganic chemistry , mineralogy , electrode , catalysis , organic chemistry , engineering
A spinel LiNi 0.5 Mn 1.5 O 4 cathode material with a porous hierarchical micro/nano architecture was successfully prepared by a urea‐assisted hydrothermal method followed by a high‐temperature calcination process. The effects of the hydrothermal duration on the structure, morphology, and electrochemical performance of the carbonate precursor and LiNi 0.5 Mn 1.5 O 4 cathode material were investigated. The results show that the degree of cation disorder (Mn 3+ content) first decreases and then increases as the hydrothermal duration increases, and the LiNi 0.5 Mn 1.5 O 4 sample synthesized with the carbonate precursor hydrothermally treated for 10 h has the lowest Mn 3+ content. However, this sample exhibits the best electrochemical performance, which can be attributed mainly to its smaller particle size and more homogeneous distribution. The formation mechanism and phase composition of the carbonate precursor were tentatively explored through time‐dependent observations. The carbonate precursor consists of three parts: the inner‐core MnCO 3 , the interlayer MnCO 3 and NiCO 3 , and the outer‐shell NiCO 3 . The formation pathway of the carbonate precursor can be generalized as a nucleation–growth–self‐assembly–Ostwald ripening mechanism for MnCO 3 and a dissolution–reaction–crystallization mechanism for NiCO 3 .