Calcium looping (CaL) is considered an ideal candidate for large-scale energy storage systems due to its high energy density, no heat loss and low cost. Its degrading performance over consecutive energy storage/release cycles under realistic conditions is the main inhibiting factor for application in concentrated solar power (CSP) systems. In this work, a novel calcium-based material with hollow microstructure was prepared using limestone, aluminum nitrate and cotton as raw materials. The effects of calcination conditions (850 ^oC, pure N₂; 950 ^oC, pure CO₂; 750 ^oC, pure H₂O; 850 ^oC, pure H₂O; 950 ^oC, pure H₂O; 950 ^oC, 60%H₂O/CO₂; 30%H₂O/CO₂) on the cyclic energy storage performance of synthesized materials were studied. The energy storage density of the synthesized materials is 2427 kJ/kg in the 10th cycle under pure N₂. The hollow tubular structure of the cotton is preserved and stabilized by the support of Ca₁₂Al₁₄O₃₃, which provides a good channel for the diffusion of CO₂ in particles. Under pure CO₂, the energy storage density of the synthesized materials after 10 cycles is maintained at 97% of its original values, while that of limestone is only maintained at 16%. The energy storage density of the synthesized materials at 850 °C in pure H₂O atmosphere is 1.13 times that at 950 °C in pure CO₂ atmosphere in the 10th cycle. 87%, 84% and 83% of the energy storage density of the synthesized materials at the first cycle are maintained after 10 cycles at the steam concentrations of 30%, 60% and 100%, respectively. The synthesized materials calcined under pure H₂O atmosphere shows the best performance at the 750 ^oC in the 10th cycle, which is 1.22 times higher than that at 950 ^oC. The presence of steam decreases the calcination temperature during the calcination process, which effectively mitigates the sintering effect.
 

energy storage; calcium-based material; calcium looping; reaction condition; steam atmosphere