Properties and reactivity of LaCuxNi1−xO3 perovskites in chemical-looping combustion for mid-temperature solar-thermal energy storage

Abstract

Solar-heat driven chemical-looping combustion (S-CLC) is an efficient method for storing solar energy. In the S-CLC process, solar heat is used to drive the endothermic reduction reaction between a hydrocarbon fuel and an oxygen carrier. The solar heat is converted into chemical energy and stored in the reduced oxygen carrier. Owing to their high reactivity at low reaction temperatures, perovskites are treated as promising oxygen carriers in S-CLC. Herein, the reactivity and regenerability of LaCuxNi1−xO3 (x = 0.025, 0.050, 0.075, 0.1, 0.2, 0.3, 0.5) perovskites are studied using methane as the fuel gas. The experimental results show that LaCu0.1Ni0.9O3 has the highest reactivity and regenerability among the synthesized materials. At a reduction temperature of 350 °C, more than 46% of the LaCu0.1Ni0.9O3 is reduced in 5 min, much higher than the amount of other LaCuxNi1−xO3 perovskites reduced under the same conditions. After 30 redox cycles, the reactivity and micrographs of LaCuxNi1−xO3 are similar to those of fresh material, indicating that LaCu0.1Ni0.9O3 has a desirable regenerability. Furthermore, no carbon deposition is observed during the reduction reaction between CH4 and LaCuxNi1−xO3. Our study is expected to provide a new method for storing mid-and-low temperature solar heat using this solid perovskite.