Calcium looping (CaL) is considered as an emerging technology to reduce CO2 emissions in power generation systems and carbon-intensive industries. The main disadvantage of this technology is reactivity decay over carbonation/calcination cycles due to sintering.The main objective of this study was to evaluate the performance of novel sorbents for CaL. Three types of pelletised CaO-based sorbents for CO2 capture were developed by adding aluminate cement, aluminate cement with seawater or alumina rich spinel to calcined limestone. Different concentrations of seawater in deionised water solutions were tested: 1, 10, 25 and 50 vol%. All samples were tested in a thermogravimetric analyser (TGA) under two different calcination conditions: mild (N2 atmosphere and 850°C during calcination) and realistic (CO2 atmosphere and 950°C during calcination).The samples were characterised using SEM and EDX. Aluminate cement CaO-based sorbents exhibited better performance in the TGA tests (25% conversion after 20 cycles achieved by limestone and 35% with aluminate cement CaO-based pellets, under mild conditions, and 11% conversion after 20 cycles with limestone compared to 15% utilising aluminate cement CaO-based pellets, under realistic conditions). However, doping had a negative effect in the reactivity of the sorbent. Moreover, alumina rich spinel CaObased sorbents showed the worst performance.