The Li4SiO4 sorbent experience deactivation caused by sintering of the sorbent and a slow sorption rate for CO2 capture at high temperatures. In this study, a novel Li4SiO4-based sorbent containing Li2SiO3 and LiAlO2 was developed to overcome the disadvantages of the Li4SiO4 sorbent for CO2 capture in the high temperature range of 550–700 °C. The regenerable Li4SiO4-based sorbent, which was prepared by physical mixing of Li2CO3 and SiO2 in a 2:1 M ratio with 10 wt% Al2O3, virtually maintained its CO2 capture capacity during multiple tests at a regeneration temperature of 700 °C. This is because well-dispersed Li2SiO3 and LiAlO2 play an important role in the cyclic stability of the Li4SiO4-based sorbent, as they prevent its sintering during multiple cycles. In addition, we found that LiAlO2 directly contributes to the formation of Li2SiO3, which results from a decrease in the molar ratio of Li2CO3 to SiO2 upon reaction of Li2CO3 with γ-alumina.