Hierarchically porous calcium-based composites synthesized by eggshell membrane templating for thermochemical energy storage of concentrated solar power

Abstract

Thermochemical energy storage (TCES) based on the calcium-looping (CaL) process is considered as a promising strategy to realize more-efficient concentrating solar power using a supercritical carbon dioxide cycle. However, developing high energy and power density, cycling stability and cost-effective calcium-based TCES materials is still a significant challenge due to their rapid deactivation induced by sintering. Herein, we report the high-performing Ca-based composites templated by eggshell membranes (ESM) using a facile sol-gel method for thermochemical energy storage. The hierarchically-ordered calcium-based materials are characterized by macroporous and mesoporous networks composed of MgO-stabilized CaO nanoparticles, which exhibit large surface area and abundant porosity enabled by highly porous interwoven fibrous structures of ESM template. The synthetic composites with 20 wt% MgO doping offers superior CO2 uptake, high carbonation rate and cycling stability during the 20 carbonation-calcination cycles. Importantly, the CaO/MgO pellets constructed by this morph-genetic material shows the TCES potential of achieving a high energy storage density of 2.58 GJ/m3, extraordinary power density of 720 W/kg, and sufficient crushing strength. It is contributed by the rapid CO2 diffusion rate and high resistance to pore-plugging and collapse derived from the three-dimensional hierarchical structures of the as-obtained materials. The excellent performance makes the ESM-templated calcium-based materials promising alternative to realize high-efficient thermochemical energy storage for concentrated solar power.