Multi-core compartmentalized liquid-in-solid capsules for fast and durable CO₂ capture under weak driving forces

Fast and durable CO₂ capture under weak-driving-force conditions remains challenging because low CO₂ partial pressure aggravates kinetic limitations while repeated operation accelerates structural degradation of absorbent carriers. Liquid-in-solid capsules offer a promising route to intensify gas-liquid contact, yet conventional single-core capsules suffer from an intrinsic trade-off among absorbent loading, mass-transfer efficiency, and mechanical robustness. Here, we report a chemistry-architecture co-design strategy that integrates data-driven optimization of a potassium carbonate (K₂CO₃)-piperazine (PZ) absorbent with microfluidic fabrication of millimeter-scale multi-core liquid-in-solid capsules. A multi-objective genetic algorithm (NSGA-II) identifies an optimal K₂CO₃:PZ molar ratio of 9:1 that balances 15 min CO₂ absorption capacity and raw-material cost and delivers a 75.22% higher average absorption rate and a 12.12% lower raw-material cost than a 30 wt% K₂CO₃ solution at 15 vol% CO₂. Under simulated flue-gas conditions (15 vol% CO₂, 103 kPa, 313.15 K, 15 min), the optimized multi-core capsules exhibited CO₂ uptake capacities 84.42% and 123.82% higher than those of single-core capsules containing an equivalent mass of core absorbent and the unencapsulated absorbent, respectively. The compartmentalized architecture also enhanced structural resilience, delivering a compressive strength 4.44 times that of single-core capsules and limiting the performance loss to 1.17% after a severe dehydration-rehydration cycle. In addition, under simulated-flue-gas conditions, the multi-core capsules retain approximately 80% of their initial 2 min CO2 absorption capacity after 50 absorption-desorption cycles. These results demonstrate that multi-core compartmentalization can simultaneously improve mass-transfer kinetics and structural robustness, providing a practical design framework for capsule-based CO₂ capture under low-partial-pressure conditions.