In-Situ observation and quantitative analysis on sintering process of Li4SiO4 sorbents

High-temperature CO2 adsorption has an attractive prospect in reducing CO2 emissions efficiently. As the core of CO2 adsorption technology, sorbents suffer from a well-known problem of capacity degradation as a result of sintering during cyclic CO2 adsorption and desorption at high temperatures. This work aims to understand the microstructural evolution of Li4SiO4, one of the most typical and promising sorbents, during CO2 capture. In-situ Transmission Electron Microscopy was used to directly capture the morphological variation of Li4SiO4 sorbents. Comprehensive characterization techniques were adopted to quantify microstructural parameters of Li4SiO4 under different conditions. The real-time shrinkage of Li4SiO4 particles was demonstrated and equations on grain growth, specific surface area reduction, and pore volume evolution were established. The work can not only reveal the reason for the reduction of CO2 capacity, but provide a theoretical guidance for the development of sintering-resistant CO2 sorbents.