Modification of CaO-based thermochemical storage particles through SiC doping and calcination strategy: Toward enhanced thermal conductivity and mechanical properties

Calcium oxide (CaO) is a promising material for thermochemical energy storage, but its poor mechanical properties and cycling stability remain a major challenge. In this study, CaO-based composite particles with different SiC doping ratio (0–20 wt%) were prepared and subjected to forming calcination at 700°C, 850°C, and 1000°C. The effects of doping ratio and forming calcination temperature on thermal conductivity, reaction stability, and mechanical properties were systematically evaluated. The results show that 10 wt% SiC doping significantly improves thermal conductivity (up to 0.971 W·m⁻¹·K⁻¹), improves strength (still 14.5 N after 20 cycles), and reduces attrition loss to 0.31 wt% after 20 cycles. However, over-doping (≥15 wt%) leads to a decrease in strength during cycling. The energy storage density and conversion rate also decrease slightly with increasing doping ratio. Particles doped with 10 wt% SiC and subjected to calcination above 850 °C showed superior overall performance in both thermal and mechanical aspects.