Solar Thermochemical CO 2 Splitting Integrated with Supercritical CO 2 Cycle for Efficient Fuel and Power Generation

Converting CO 2 into fuels via solar-driven thermochemical cycles of metal oxides is promising to address global climate change and energy crisis challenges simultaneously. However, it suffers from low energy conversion efficiency ( η en ) due to high sensible heat losses when swinging between reduction and oxidation cycles, and a single product of fuels can hardly meet multiple kinds of energy demands. Here, we propose an alternative way to upsurge energy conversion efficiency by integrating solar thermochemical CO 2 splitting with a supercritical CO 2 thermodynamic cycle. When gas phase heat recovery ( ε gg ) is equal to 0.9, the highest energy conversion efficiency of 20.4% is obtained at the optimal cycle high pressure of 260 bar. In stark contrast, the highest energy conversion efficiency is only 9.8% for conventional solar thermochemical CO 2 splitting without including a supercritical CO 2 cycle. The superior performance is attributed to efficient harvesting of waste heat and synergy of CO 2 splitting cycles with supercritical CO 2 cycles. This work provides alternative routes for promoting the development and deployment of solar thermochemical CO 2 splitting techniques.