Amine-impregnated　adsorbents　are　promising　alternatives　to　aqueous　amines　for　CO2　capture.　However,　the　diffusion-controlled　CO2　adsorption　process　is　a　significant　issue　associated　with　them,　resulting　in　the　insufficient　utilization　of　amine　groups.　Herein,　we　propose　the　use　of　functionalized　ionic　liquids　1-ethyl-3-methylimidazolium　acetate　([emim][Ac])　with　chemical　reactivity　to　CO2　and　low　viscosity　as　the　additive　to　amine-impregnated　adsorbents.　The　key　is　that　[emim][Ac]　does　not　show　drastic　increase　in　viscosity　after　reacting　with　CO2.　Taking　the　polyethyleneimine　(PEI)-impregnated　SBA-15　as　a　model　system,　it　is　found　that　the　CO2　capacities　of　PEI/SBA-15　composites　are　improved　by　86%,　and　the　active　site　efficiencies　are　improved　by　270%,　after　the　addition　of　[emim][Ac].　The　addition　of　[emim][Ac]　to　PEI/SBA-15　composites　also　helps　improve　the　CO2　adsorption　rate　and　recycling　stability　of　composites.　Therefore,　[emim][Ac]　offers　the　opportunity　to　fabricate　amine-impregnated　adsorbents　with　simultaneously　improved　CO2　capacities,　adsorption　kinetics,　and　recycling　stability.　©　2018　American　Institute　of　Chemical　Engineers　AIChE　J,　64:　3671–3680,　2018.　©　2018　American　Institute　of　Chemical　Engineers