Thermodynamic and experimental analysis of Ni-Co-Mn carbonate precursor synthesis for Li-rich cathode materials

Autor: Yunjiao Li, Georgios Kolliopoulos, Vladimiros G. Papangelakis, Yongxiang Chen, Shiyi Deng
Rok vydání: 2020
Předmět:
Zdroj: Ionics. 26:2747-2755
ISSN: 1862-0760
0947-7047
DOI: 10.1007/s11581-020-03439-2
Popis: The Eh-pH diagrams for Ni-Co-Mn-CO3-H2O system at various temperatures and ion concentrations are simulated via OLI studio based on the fundamentals of thermodynamic equilibrium. A co-existence area for NiCO3, CoCO3, and MnCO3 is observed visually from the Eh-pH diagrams, which thermodynamically proves the stability of these species in aqueous solutions, and the possibility of co-precipitating polymetallic carbonate. The simulation results also demonstrate that a higher temperature and/or a more dilute solution are not in favor of the co-precipitation. With the predicted pH ranges from the Eh-pH diagrams, a confirmative experiment was conducted to synthesize Ni0.13Co0.13Mn0.54(CO3)0.8, the precursor for preparing Li1.2Ni0.13Co0.13Mn0.54O2, which is a promising cathode material for next-generation LIBs. The physical properties of both materials are characterized in detail, and the electrochemical performance for the final cathode material was tested. The results show that Ni2+, Co2+, and Mn2+ ions in solution are homogeneously co-precipitated in the form of polymetallic carbonate. The Li1.2Ni0.13Co0.13Mn0.54O2 material obtained from the carbonate precursor has a typical structure of Li- and Mn-rich cathodes and yields an initial discharge capacity of 296.0 mAh g−1 at 0.1 C and 188.1 mAh g−1 after 100 cycles at 1 C rate. It was verified that the OLI-assisted Eh-pH simulation is consistent with the experimental measurements.
Databáze: OpenAIRE
Externí odkaz: