Biphasic absorbents have attracted considerable attention because they can reduce the energy requirements of solvent 

regeneration during CO2 capture. In this study, a water-lean biphasic solvent system was developed by introducing polyether

solvents into an aqueous amine solution. As the n-octanol-water partition coefficient (log P) of the polyether solvents

increased, the solvent system transitioned from a homogeneous phase to a liquid-liquid biphasic system during 

CO2 absorption. Solvent screening identified the 3-(methylamino)propylamine (MAPA) / triethylene glycol monobutyl 

ether (TEGMBE) /water system as a promising formulation due to its high cyclic capacity and low viscosity. 13C NMR 

analysis revealed that CO2 absorption products such as MAPA-carbamate, protonated MAPA, and CO3

2-/ HCO3- were predominantly located in the lower phase. TEGMBE was predominantly distributed in the upper phase and functions as a physically inert phase-separating component. The cyclic loading and volume distribution of the rich phase were affected 

by TEGMBE concentration. When the TEGMBE content is 50 wt%, the CO2-rich phase loading (αrich) and corresponding 

cyclic capacity (Δα) within the rich phase reached 279 gCO2/Lsolvent and 143 gCO2/Lsolvent, respectively, representing 

increases of 250% in rich loading and 220% in cyclic capacity compared with a conventional 5 M monoethanolamine 

(MEA) aqueous solution. In addition, the volume of the CO2 rich phase was reduced by 54% relative to the MEA aqueous 

solution. This high concentration significantly reduces the liquid volume to be processed in the subsequent regeneration 

step, thereby offering substantial potential for energy savings in the desorber.