Recent advances in post-combustion CaO-based CO2 capture and thermochemical energy storage through calcium looping process; the state-of-the-art and prospective for practicability

Global warming represents a significant environmental challenge, prompting extensive research into Carbon Capture, Utilization, and Storage (CCUS) technologies. Calcium oxide (CaO)-based sorbents, particularly within the Calcium Looping (CaL) process, have emerged as a primary focus for high-temperature post-combustion CO 2 capture and thermochemical energy storage (TCES). To address sintering and sustain sorbent performance over multiple CaL cycles, various enhancement strategies for nanostructured and granule-shaped CaO have been developed. Nevertheless, comprehensive reviews of recent advancements remain limited, underscoring the necessity to critically assess these developments for practical implementation. To this end, a timely review is required to identify the more sophisticated and efficient method for developing the best structurally operational CaO sorbents, considering all effective operational and structural conditions. This study, motivated by the significant impact of CaO texture on its CO 2 capture activity and TCES performance, first examines conventional CaO-based preparation methodologies, followed by a systematic analysis of contemporary advancements in the development of modified sorbents. Particular emphasis is placed on comprehensively evaluating optimized modification strategies for enhanced CO 2 capture capacity. This review thoroughly examines the CO 2 capture capacity and TCES potential of modified CaO powders and granules to assess the effectiveness of different textural and functional improvements. It systematically compares the performance of various enhancement methods for nanostructured and granule-shaped CaO sorbents under laboratory and semi-practical conditions. The paper also discusses latest advances in improving the fluidity of CaO-based sorbents in fluidized-bed systems are also discussed, along with recent developments in using CaL for TCES. Persistent issues like sorbent sintering are addressed through strategies such as doping, particle design, and advanced synthesis, offering a comprehensive outlook on the progress and future prospects of CaL technology.