<p>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 (α_rich) 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&#xa0;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.</p>