CO₂Chemisorption and Cyclability Analyses of Lithium Aluminate Polymorphs (α- and β-Li₅AlO₄)

Abstract

The α- and β-Li5AlO4 polymorphs were synthesized using a solid-state reaction. The polymorphs were then characterized by X-ray diffraction (XRD), X-ray thermodiffraction (XRTD), and N2 adsorption. To determine the CO2 chemisorption capacity, the lithium aluminate polymorphs were analyzed thermogravimetrically in the presence of a CO2 flux. In addition, a cyclability study was performed on these ceramic materials. Although the results appear very similar for the two phases, α-Li5AlO4 exhibits a better CO2 chemisorption performance. The cyclic performance tests indicate that both materials exhibit a gradually reduced chemisorption capacity after multicycle processes. However, even after many cycles, the chemisorption capacity is considerably high in comparison to other lithium ceramics tested as CO2 absorbents.

Influence of the K‐, Na‐ and K‐Na‐carbonate additions during the CO2 chemisorption on lithium oxosilicate (Li8SiO6)

“…Th e samples chemisorbed between 1.5 and 2.5 mmol CO 2 per ceramic gram, which represents good values in comparison to other lithium ceramics. 37 …”

CO2 chemisorption and cyclability analyses in α−Li5AlO4: effects of Na2CO3 and K2CO3 addition

“…The α‐Li 5 AlO 4 pellets were heated to 500 °C for 24 h and slowly cooled down to room temperature. After the thermal treatment the α−Li 5 AlO 4 pellets were pulverized . To obtain pure α−Li 5 AlO 4 , 30 mol% excess of lithium was used, as lithium tends to sublimate .…”

“…Li 5 AlO 4 has two polymorphs, at low and high temperatures, α−Li 5 AlO 4 and β−Li 5 AlO 4 , and the α→β structural transition occurs at around 780 °C. Although, Li 5 AlO 4 has a CO 2 theoretical chemisorption of 15.9 mmol/g, experimentally it has been reported chemisorptions of 15.3 and 12.1 mmol/g for the β−Li 5 AlO 4 and α−Li 5 AlO 4 phases, respectively . Furthermore, when Li 5 AlO 4 reacts with CO 2 , LiAlO 2 is produced.…”

“…However, the ceramics most extensively studied are the lithium zirconates, the lithium silicates and the sodium zirconate . Other lithium ceramics tested as possible CO 2 captors are lithium cuprate, lithium ferrite, lithium titanate, and lithium aluminates (LiAlO 2 and Li 5 AlO 4 ) …”

First-principles study of the structural, electronic, dynamical, and thermodynamic properties of Li5AlO4

“…Thus, Li 5 AlO 4 may be more suitable as a tritium breeder material than g-LiAlO 2 . In addition, Li 5 AlO 4 can be used as a CO 2 sorbent to reduce global warming owing to its high CO 2 chemisorption capacity [6,7], or employed as a solid electrolyte for thermal battery applications [8e10].…”