Ni/CaO, a low-cost dual-functional material (DFM), has been widely studied for integrated COsub.2 capture and hydrogenation. The core of this dual-functional material should possess both good COsub.2 capture–conversion performance and structural stability. Here, we synthesized Ni/CaO DFMs modified with alkali metals (Na, K, and Li) through a combination of precipitation and combustion methods. It was found that Na-modified Ni/CaO (Na-Ni/CaO) DFM offered stable COsub.2 capture–conversion activity over 20 cycles, with a high COsub.2 capture capacity of 10.8 mmol/g and a high COsub.2 conversion rate of 60.5% at the same temperature of 650 °C. The enhanced COsub.2 capture capacity was attributed to the improved surface basicity of Na-Ni/CaO. In addition, the incorporation of Na into DFMs had a favorable effect on the formation of double salts, which shorten the COsub.2 capture and release process and promoted DFM stability by hindering their aggregation and the sintering of DFMs.