Nonaqueous liquid–liquid CO 2 phase change absorbents (CPCAs) have garnered significant attention due to their potential for efficient and energy-saving CO 2 capture in the amine-scrubbing process. This study introduces a novel nonaqueous CPCA that utilizes aminoethylethanolamine (AEEA) as the main amine absorbent, dimethyl sulfoxide (DMSO) as the organic solvent, and N -ethylmorpholine (NEM) as the phase separator. To mitigate the high viscosity of the rich phase in CPCA, diethanolamine (DEA) is introduced as a viscosity regulator, which reduces the viscosity by 79.3% by weakening the intermolecular hydrogen bonding in the CO 2 products. Notably, the optimized CPCA of A 20 E 10 D 40 N 30 demonstrates a high cyclic capacity of 2.94 mol·kg –1 and a low regeneration energy consumption of 1.79 GJ·t –1 of CO 2 . Overall, the efficient CO 2 capture performance, low regeneration energy consumption, and minimal corrosivity make this CPCA a promising candidate for industrial CO 2 capture applications.