Coupling effects of thermodynamics in multiple ion co-precipitation for precursors towards a layered oxide cathode
The co-precipitation process is the most frequently employed method to realize the simultaneous stoichiometric crystallization of multiple ions. The precipitation of different elements under a driving force can directly and primarily determine the degree of homogeneity of the co-precipitation produc...
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Published in | Materials advances Vol. 2; no. 11; pp. 3752 - 3759 |
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Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
08.06.2021
|
Online Access | Get full text |
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Summary: | The co-precipitation process is the most frequently employed method to realize the simultaneous stoichiometric crystallization of multiple ions. The precipitation of different elements under a driving force can directly and primarily determine the degree of homogeneity of the co-precipitation product. Unlike individual element crystallization, the multiple ion coexistence co-precipitation process is complicated and a coupling effect is involved, as the thermodynamic behaviour of certain elements is much superior to that of others. This coupling effect can dramatically influence the whole thermodynamic behaviour in the liquid solution. Therefore, in order to achieve a high-quality product or precursor with various elements in a homogeneous distribution, the co-precipitation process can be efficiently controlled and balanced by the coupling effect resulting from the addition of certain elements. In an environment where Co
2+
, Ni
2+
, and Mn
2+
ions coexist, owing to the thermodynamic coupling effect, the superior high supersaturation of Al
3+
and the more negative change in the Gibbs free energy (Δ
G
) can efficiently balance the whole crystallization reaction by realizing a consistent precipitation driving force among the various ions, accelerating the precipitation of Ni
2+
and Mn
2+
ions and inhibiting the precipitation of Co
2+
ions. Meanwhile, based on the initial formation of the Al(OH)
3
seed crystals in the solution, multiple ions in the solution can be adsorbed and thus grow on the surface of Al(OH)
3
to completely precipitate. The obtained Li-rich cathode material has demonstrated excellent electrochemical performance which can be attributed to the high quality precursor (0.54MnCO
3
·0.13NiCO
3
·0.125CoCO
3
·0.005Al(OH)
3
) with a homogeneous distribution of elements.
The co-precipitation process was controlled and the different driving forces were balanced based on the coupling effects of thermodynamics. |
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Bibliography: | Electronic supplementary information (ESI) available: These might include comments relevant to but not central to the matter under discussion, limited experimental and spectral data, and crystallographic data. See DOI 10.1039/d0ma00614a |
ISSN: | 2633-5409 2633-5409 |
DOI: | 10.1039/d0ma00614a |