Reinvestigations of the Li2O–Al2O3 system. Part I: LiAlO2 and Li3AlO3

Piotr Tabero,Artur Frąckowiak,Grażyna Dąbrowska

doi:10.2478/pjct-2021-0027

Piotr Tabero, Artur Frąckowiak + Show 1 more

Open Access

https://doi.org/10.2478/pjct-2021-0027

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Abstract

Abstract Reinvestigations of the Li2O–Al2O3 system focused on the synthesis and properties of LiAlO2 and Li3AlO3 phases have been performed with the help of XRD and IR measuring techniques and Li2CO3, LiOH·H2O, Al2O3-sl., α-Al2O3, Al(NO3)3·9H2O and boehmite as reactants. Results of investigations have shown the formation of α-, β-, and γ- polymorphs of LiAlO2. It was found that only the use of LiOH·H2O as a reactant yields to β-LiAlO2 as a reaction product. On the other hand, it was proved that Li3AlO3 does not form in the Li2O–Al2O3 system. A new method for the synthesis of α-LiAlO2 was developed, consisting in grinding the mixture of Li2CO3 and Al(NO3)3·9H2O and heating the obtained paste at the temperature range of 400–600 °C. The IR spectroscopy was used to characterize obtained phases.

Highlights

Compounds containing lithium have been the subject of comprehensive research for many years due to many different industrial applications, including the production of glass and heat-resistant ceramics[1,2,3], luminescent ionizing radiation detectors[4, 5], carbonate fuel cell components[6,7,8,9], carbon dioxide absorbents[10] and solid electrolytes used for the production of lithium-ion batteries[11, 12]
The literature review has shown that 5 compounds are formed in the two-component system of Li2O–Al2O3 oxides: Li5AlO4, Li3AlO3, LiAl2O3.5, LiAlO2 and LiAl5O8
No phase diagram of the Li2O–Al2O3 system has been developed in the entire concentration range of the components

Summary

INTRODUCTION

Compounds containing lithium have been the subject of comprehensive research for many years due to many different industrial applications, including the production of glass and heat-resistant ceramics[1,2,3], luminescent ionizing radiation detectors[4, 5], carbonate fuel cell components[6,7,8,9], carbon dioxide absorbents[10] and solid electrolytes used for the production of lithium-ion batteries[11, 12]. The conducted literature review showed that the authors of the studies disagreed as to the temperature of phase transitions and the thermal stability of the LiAlO2 polymorphs. Isupov et al.[49] investigated the effect of the gaseous atmosphere on the type of LiAlO2 modification produced using gibbsite and Li2CO3 mixture They showed that during synthesis at 800 oC in air with typical partial water pressure of 1300 Pa forms α-LiAlO2 contaminated with small amounts of γ-LiAlO2. La Ginestra and co-workers[53], as a result of heating at 400 oC for 500 hours of the mixture of γ-Al2O3 and Li2O2 obtained the Li3AlO3 phase and presented the powder diffraction pattern of this compound.

RESULTS AND DISCUSSION

CONCLUSIONS

LITERATURE CITED